drivers/acpi/video.c

   1 /*
   2  *  video.c - ACPI Video Driver
   3  *
   4  *  Copyright (C) 2004 Luming Yu <luming.yu@intel.com>
   5  *  Copyright (C) 2004 Bruno Ducrot <ducrot@poupinou.org>
   6  *  Copyright (C) 2006 Thomas Tuttle <linux-kernel@ttuttle.net>
   7  *
   8  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or (at
  13  *  your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful, but
  16  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  *  General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License along
  21  *  with this program; if not, write to the Free Software Foundation, Inc.,
  22  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  23  *
  24  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  25  */
  26
  27 #include <linux/kernel.h>
  28 #include <linux/module.h>
  29 #include <linux/init.h>
  30 #include <linux/types.h>
  31 #include <linux/list.h>
  32 #include <linux/mutex.h>
  33 #include <linux/input.h>
  34 #include <linux/backlight.h>
  35 #include <linux/thermal.h>
  36 #include <linux/sort.h>
  37 #include <linux/pci.h>
  38 #include <linux/pci_ids.h>
  39 #include <linux/slab.h>
  40 #include <linux/dmi.h>
  41 #include <linux/suspend.h>
  42 #include <linux/acpi.h>
  43 #include <acpi/video.h>
  44 #include <asm/uaccess.h>
  45
  46 #include "internal.h"
  47
  48 #define ACPI_VIDEO_BUS_NAME             "Video Bus"
  49 #define ACPI_VIDEO_DEVICE_NAME          "Video Device"
  50 #define ACPI_VIDEO_NOTIFY_SWITCH        0x80
  51 #define ACPI_VIDEO_NOTIFY_PROBE         0x81
  52 #define ACPI_VIDEO_NOTIFY_CYCLE         0x82
  53 #define ACPI_VIDEO_NOTIFY_NEXT_OUTPUT   0x83
  54 #define ACPI_VIDEO_NOTIFY_PREV_OUTPUT   0x84
  55
  56 #define ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS      0x85
  57 #define ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS        0x86
  58 #define ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS        0x87
  59 #define ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS       0x88
  60 #define ACPI_VIDEO_NOTIFY_DISPLAY_OFF           0x89
  61
  62 #define MAX_NAME_LEN    20
  63
  64 #define _COMPONENT              ACPI_VIDEO_COMPONENT
  65 ACPI_MODULE_NAME("video");
  66
  67 MODULE_AUTHOR("Bruno Ducrot");
  68 MODULE_DESCRIPTION("ACPI Video Driver");
  69 MODULE_LICENSE("GPL");
  70
  71 static bool brightness_switch_enabled = 1;
  72 module_param(brightness_switch_enabled, bool, 0644);
  73
  74 /*
  75  * By default, we don't allow duplicate ACPI video bus devices
  76  * under the same VGA controller
  77  */
  78 static bool allow_duplicates;
  79 module_param(allow_duplicates, bool, 0644);
  80
  81 /*
  82  * For Windows 8 systems: used to decide if video module
  83  * should skip registering backlight interface of its own.
  84  */
  85 static int use_native_backlight_param = -1;
  86 module_param_named(use_native_backlight, use_native_backlight_param, int, 0444);
  87 static bool use_native_backlight_dmi = false;
  88
  89 static int register_count;
  90 static struct mutex video_list_lock;
  91 static struct list_head video_bus_head;
  92 static int acpi_video_bus_add(struct acpi_device *device);
  93 static int acpi_video_bus_remove(struct acpi_device *device);
  94 static void acpi_video_bus_notify(struct acpi_device *device, u32 event);
  95
  96 static const struct acpi_device_id video_device_ids[] = {
  97         {ACPI_VIDEO_HID, 0},
  98         {"", 0},
  99 };
 100 MODULE_DEVICE_TABLE(acpi, video_device_ids);
 101
 102 static struct acpi_driver acpi_video_bus = {
 103         .name = "video",
 104         .class = ACPI_VIDEO_CLASS,
 105         .ids = video_device_ids,
 106         .ops = {
 107                 .add = acpi_video_bus_add,
 108                 .remove = acpi_video_bus_remove,
 109                 .notify = acpi_video_bus_notify,
 110                 },
 111 };
 112
 113 struct acpi_video_bus_flags {
 114         u8 multihead:1;         /* can switch video heads */
 115         u8 rom:1;               /* can retrieve a video rom */
 116         u8 post:1;              /* can configure the head to */
 117         u8 reserved:5;
 118 };
 119
 120 struct acpi_video_bus_cap {
 121         u8 _DOS:1;              /* Enable/Disable output switching */
 122         u8 _DOD:1;              /* Enumerate all devices attached to display adapter */
 123         u8 _ROM:1;              /* Get ROM Data */
 124         u8 _GPD:1;              /* Get POST Device */
 125         u8 _SPD:1;              /* Set POST Device */
 126         u8 _VPO:1;              /* Video POST Options */
 127         u8 reserved:2;
 128 };
 129
 130 struct acpi_video_device_attrib {
 131         u32 display_index:4;    /* A zero-based instance of the Display */
 132         u32 display_port_attachment:4;  /* This field differentiates the display type */
 133         u32 display_type:4;     /* Describe the specific type in use */
 134         u32 vendor_specific:4;  /* Chipset Vendor Specific */
 135         u32 bios_can_detect:1;  /* BIOS can detect the device */
 136         u32 depend_on_vga:1;    /* Non-VGA output device whose power is related to
 137                                    the VGA device. */
 138         u32 pipe_id:3;          /* For VGA multiple-head devices. */
 139         u32 reserved:10;        /* Must be 0 */
 140         u32 device_id_scheme:1; /* Device ID Scheme */
 141 };
 142
 143 struct acpi_video_enumerated_device {
 144         union {
 145                 u32 int_val;
 146                 struct acpi_video_device_attrib attrib;
 147         } value;
 148         struct acpi_video_device *bind_info;
 149 };
 150
 151 struct acpi_video_bus {
 152         struct acpi_device *device;
 153         u8 dos_setting;
 154         struct acpi_video_enumerated_device *attached_array;
 155         u8 attached_count;
 156         struct acpi_video_bus_cap cap;
 157         struct acpi_video_bus_flags flags;
 158         struct list_head video_device_list;
 159         struct mutex device_list_lock;  /* protects video_device_list */
 160         struct list_head entry;
 161         struct input_dev *input;
 162         char phys[32];  /* for input device */
 163         struct notifier_block pm_nb;
 164 };
 165
 166 struct acpi_video_device_flags {
 167         u8 crt:1;
 168         u8 lcd:1;
 169         u8 tvout:1;
 170         u8 dvi:1;
 171         u8 bios:1;
 172         u8 unknown:1;
 173         u8 notify:1;
 174         u8 reserved:1;
 175 };
 176
 177 struct acpi_video_device_cap {
 178         u8 _ADR:1;              /* Return the unique ID */
 179         u8 _BCL:1;              /* Query list of brightness control levels supported */
 180         u8 _BCM:1;              /* Set the brightness level */
 181         u8 _BQC:1;              /* Get current brightness level */
 182         u8 _BCQ:1;              /* Some buggy BIOS uses _BCQ instead of _BQC */
 183         u8 _DDC:1;              /* Return the EDID for this device */
 184 };
 185
 186 struct acpi_video_brightness_flags {
 187         u8 _BCL_no_ac_battery_levels:1; /* no AC/Battery levels in _BCL */
 188         u8 _BCL_reversed:1;             /* _BCL package is in a reversed order */
 189         u8 _BQC_use_index:1;            /* _BQC returns an index value */
 190 };
 191
 192 struct acpi_video_device_brightness {
 193         int curr;
 194         int count;
 195         int *levels;
 196         struct acpi_video_brightness_flags flags;
 197 };
 198
 199 struct acpi_video_device {
 200         unsigned long device_id;
 201         struct acpi_video_device_flags flags;
 202         struct acpi_video_device_cap cap;
 203         struct list_head entry;
 204         struct acpi_video_bus *video;
 205         struct acpi_device *dev;
 206         struct acpi_video_device_brightness *brightness;
 207         struct backlight_device *backlight;
 208         struct thermal_cooling_device *cooling_dev;
 209 };
 210
 211 static const char device_decode[][30] = {
 212         "motherboard VGA device",
 213         "PCI VGA device",
 214         "AGP VGA device",
 215         "UNKNOWN",
 216 };
 217
 218 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data);
 219 static void acpi_video_device_rebind(struct acpi_video_bus *video);
 220 static void acpi_video_device_bind(struct acpi_video_bus *video,
 221                                    struct acpi_video_device *device);
 222 static int acpi_video_device_enumerate(struct acpi_video_bus *video);
 223 static int acpi_video_device_lcd_set_level(struct acpi_video_device *device,
 224                         int level);
 225 static int acpi_video_device_lcd_get_level_current(
 226                         struct acpi_video_device *device,
 227                         unsigned long long *level, bool raw);
 228 static int acpi_video_get_next_level(struct acpi_video_device *device,
 229                                      u32 level_current, u32 event);
 230 static int acpi_video_switch_brightness(struct acpi_video_device *device,
 231                                          int event);
 232
 233 static bool acpi_video_use_native_backlight(void)
 234 {
 235         if (use_native_backlight_param != -1)
 236                 return use_native_backlight_param;
 237         else
 238                 return use_native_backlight_dmi;
 239 }
 240
 241 static bool acpi_video_verify_backlight_support(void)
 242 {
 243         if (acpi_osi_is_win8() && acpi_video_use_native_backlight() &&
 244             backlight_device_registered(BACKLIGHT_RAW))
 245                 return false;
 246         return acpi_video_backlight_support();
 247 }
 248
 249 /* backlight device sysfs support */
 250 static int acpi_video_get_brightness(struct backlight_device *bd)
 251 {
 252         unsigned long long cur_level;
 253         int i;
 254         struct acpi_video_device *vd = bl_get_data(bd);
 255
 256         if (acpi_video_device_lcd_get_level_current(vd, &cur_level, false))
 257                 return -EINVAL;
 258         for (i = 2; i < vd->brightness->count; i++) {
 259                 if (vd->brightness->levels[i] == cur_level)
 260                         /*
 261                          * The first two entries are special - see page 575
 262                          * of the ACPI spec 3.0
 263                          */
 264                         return i - 2;
 265         }
 266         return 0;
 267 }
 268
 269 static int acpi_video_set_brightness(struct backlight_device *bd)
 270 {
 271         int request_level = bd->props.brightness + 2;
 272         struct acpi_video_device *vd = bl_get_data(bd);
 273
 274         return acpi_video_device_lcd_set_level(vd,
 275                                 vd->brightness->levels[request_level]);
 276 }
 277
 278 static const struct backlight_ops acpi_backlight_ops = {
 279         .get_brightness = acpi_video_get_brightness,
 280         .update_status  = acpi_video_set_brightness,
 281 };
 282
 283 /* thermal cooling device callbacks */
 284 static int video_get_max_state(struct thermal_cooling_device *cooling_dev, unsigned
 285                                long *state)
 286 {
 287         struct acpi_device *device = cooling_dev->devdata;
 288         struct acpi_video_device *video = acpi_driver_data(device);
 289
 290         *state = video->brightness->count - 3;
 291         return 0;
 292 }
 293
 294 static int video_get_cur_state(struct thermal_cooling_device *cooling_dev, unsigned
 295                                long *state)
 296 {
 297         struct acpi_device *device = cooling_dev->devdata;
 298         struct acpi_video_device *video = acpi_driver_data(device);
 299         unsigned long long level;
 300         int offset;
 301
 302         if (acpi_video_device_lcd_get_level_current(video, &level, false))
 303                 return -EINVAL;
 304         for (offset = 2; offset < video->brightness->count; offset++)
 305                 if (level == video->brightness->levels[offset]) {
 306                         *state = video->brightness->count - offset - 1;
 307                         return 0;
 308                 }
 309
 310         return -EINVAL;
 311 }
 312
 313 static int
 314 video_set_cur_state(struct thermal_cooling_device *cooling_dev, unsigned long state)
 315 {
 316         struct acpi_device *device = cooling_dev->devdata;
 317         struct acpi_video_device *video = acpi_driver_data(device);
 318         int level;
 319
 320         if (state >= video->brightness->count - 2)
 321                 return -EINVAL;
 322
 323         state = video->brightness->count - state;
 324         level = video->brightness->levels[state - 1];
 325         return acpi_video_device_lcd_set_level(video, level);
 326 }
 327
 328 static const struct thermal_cooling_device_ops video_cooling_ops = {
 329         .get_max_state = video_get_max_state,
 330         .get_cur_state = video_get_cur_state,
 331         .set_cur_state = video_set_cur_state,
 332 };
 333
 334 /*
 335  * --------------------------------------------------------------------------
 336  *                             Video Management
 337  * --------------------------------------------------------------------------
 338  */
 339
 340 static int
 341 acpi_video_device_lcd_query_levels(struct acpi_video_device *device,
 342                                    union acpi_object **levels)
 343 {
 344         int status;
 345         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 346         union acpi_object *obj;
 347
 348
 349         *levels = NULL;
 350
 351         status = acpi_evaluate_object(device->dev->handle, "_BCL", NULL, &buffer);
 352         if (!ACPI_SUCCESS(status))
 353                 return status;
 354         obj = (union acpi_object *)buffer.pointer;
 355         if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
 356                 printk(KERN_ERR PREFIX "Invalid _BCL data\n");
 357                 status = -EFAULT;
 358                 goto err;
 359         }
 360
 361         *levels = obj;
 362
 363         return 0;
 364
 365 err:
 366         kfree(buffer.pointer);
 367
 368         return status;
 369 }
 370
 371 static int
 372 acpi_video_device_lcd_set_level(struct acpi_video_device *device, int level)
 373 {
 374         int status;
 375         int state;
 376
 377         status = acpi_execute_simple_method(device->dev->handle,
 378                                             "_BCM", level);
 379         if (ACPI_FAILURE(status)) {
 380                 ACPI_ERROR((AE_INFO, "Evaluating _BCM failed"));
 381                 return -EIO;
 382         }
 383
 384         device->brightness->curr = level;
 385         for (state = 2; state < device->brightness->count; state++)
 386                 if (level == device->brightness->levels[state]) {
 387                         if (device->backlight)
 388                                 device->backlight->props.brightness = state - 2;
 389                         return 0;
 390                 }
 391
 392         ACPI_ERROR((AE_INFO, "Current brightness invalid"));
 393         return -EINVAL;
 394 }
 395
 396 /*
 397  * For some buggy _BQC methods, we need to add a constant value to
 398  * the _BQC return value to get the actual current brightness level
 399  */
 400
 401 static int bqc_offset_aml_bug_workaround;
 402 static int __init video_set_bqc_offset(const struct dmi_system_id *d)
 403 {
 404         bqc_offset_aml_bug_workaround = 9;
 405         return 0;
 406 }
 407
 408 static int __init video_set_use_native_backlight(const struct dmi_system_id *d)
 409 {
 410         use_native_backlight_dmi = true;
 411         return 0;
 412 }
 413
 414 static struct dmi_system_id video_dmi_table[] __initdata = {
 415         /*
 416          * Broken _BQC workaround http://bugzilla.kernel.org/show_bug.cgi?id=13121
 417          */
 418         {
 419          .callback = video_set_bqc_offset,
 420          .ident = "Acer Aspire 5720",
 421          .matches = {
 422                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 423                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5720"),
 424                 },
 425         },
 426         {
 427          .callback = video_set_bqc_offset,
 428          .ident = "Acer Aspire 5710Z",
 429          .matches = {
 430                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 431                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5710Z"),
 432                 },
 433         },
 434         {
 435          .callback = video_set_bqc_offset,
 436          .ident = "eMachines E510",
 437          .matches = {
 438                 DMI_MATCH(DMI_BOARD_VENDOR, "EMACHINES"),
 439                 DMI_MATCH(DMI_PRODUCT_NAME, "eMachines E510"),
 440                 },
 441         },
 442         {
 443          .callback = video_set_bqc_offset,
 444          .ident = "Acer Aspire 5315",
 445          .matches = {
 446                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 447                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5315"),
 448                 },
 449         },
 450         {
 451          .callback = video_set_bqc_offset,
 452          .ident = "Acer Aspire 7720",
 453          .matches = {
 454                 DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
 455                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 7720"),
 456                 },
 457         },
 458         {
 459          .callback = video_set_use_native_backlight,
 460          .ident = "ThinkPad T430 and T430s",
 461          .matches = {
 462                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 463                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad T430"),
 464                 },
 465         },
 466         {
 467          .callback = video_set_use_native_backlight,
 468          .ident = "ThinkPad X230",
 469          .matches = {
 470                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 471                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X230"),
 472                 },
 473         },
 474         {
 475          .callback = video_set_use_native_backlight,
 476         .ident = "ThinkPad X1 Carbon",
 477         .matches = {
 478                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 479                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X1 Carbon"),
 480                 },
 481         },
 482         {
 483          .callback = video_set_use_native_backlight,
 484          .ident = "Lenovo Yoga 13",
 485          .matches = {
 486                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 487                 DMI_MATCH(DMI_PRODUCT_VERSION, "Lenovo IdeaPad Yoga 13"),
 488                 },
 489         },
 490         {
 491         .callback = video_set_use_native_backlight,
 492         .ident = "Thinkpad Helix",
 493         .matches = {
 494                 DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 495                 DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad Helix"),
 496                 },
 497         },
 498         {
 499          .callback = video_set_use_native_backlight,
 500          .ident = "Dell Inspiron 7520",
 501          .matches = {
 502                 DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
 503                 DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 7520"),
 504                 },
 505         },
 506         {
 507          .callback = video_set_use_native_backlight,
 508          .ident = "Acer Aspire 5733Z",
 509          .matches = {
 510                 DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 511                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5733Z"),
 512                 },
 513         },
 514         {
 515          .callback = video_set_use_native_backlight,
 516          .ident = "Acer Aspire 5742G",
 517          .matches = {
 518                 DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 519                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5742G"),
 520                 },
 521         },
 522         {
 523          .callback = video_set_use_native_backlight,
 524          .ident = "Acer Aspire V5-431",
 525          .matches = {
 526                 DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
 527                 DMI_MATCH(DMI_PRODUCT_NAME, "Aspire V5-431"),
 528                 },
 529         },
 530         {
 531         .callback = video_set_use_native_backlight,
 532         .ident = "HP ProBook 4340s",
 533         .matches = {
 534                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 535                 DMI_MATCH(DMI_PRODUCT_VERSION, "HP ProBook 4340s"),
 536                 },
 537         },
 538         {
 539         .callback = video_set_use_native_backlight,
 540         .ident = "HP ProBook 2013 models",
 541         .matches = {
 542                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 543                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ProBook "),
 544                 DMI_MATCH(DMI_PRODUCT_NAME, " G1"),
 545                 },
 546         },
 547         {
 548         .callback = video_set_use_native_backlight,
 549         .ident = "HP EliteBook 2013 models",
 550         .matches = {
 551                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 552                 DMI_MATCH(DMI_PRODUCT_NAME, "HP EliteBook "),
 553                 DMI_MATCH(DMI_PRODUCT_NAME, " G1"),
 554                 },
 555         },
 556         {
 557         .callback = video_set_use_native_backlight,
 558         .ident = "HP ZBook 14",
 559         .matches = {
 560                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 561                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ZBook 14"),
 562                 },
 563         },
 564         {
 565         .callback = video_set_use_native_backlight,
 566         .ident = "HP ZBook 15",
 567         .matches = {
 568                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 569                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ZBook 15"),
 570                 },
 571         },
 572         {
 573         .callback = video_set_use_native_backlight,
 574         .ident = "HP ZBook 17",
 575         .matches = {
 576                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 577                 DMI_MATCH(DMI_PRODUCT_NAME, "HP ZBook 17"),
 578                 },
 579         },
 580         {
 581         .callback = video_set_use_native_backlight,
 582         .ident = "HP EliteBook 8780w",
 583         .matches = {
 584                 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
 585                 DMI_MATCH(DMI_PRODUCT_NAME, "HP EliteBook 8780w"),
 586                 },
 587         },
 588         {}
 589 };
 590
 591 static unsigned long long
 592 acpi_video_bqc_value_to_level(struct acpi_video_device *device,
 593                               unsigned long long bqc_value)
 594 {
 595         unsigned long long level;
 596
 597         if (device->brightness->flags._BQC_use_index) {
 598                 /*
 599                  * _BQC returns an index that doesn't account for
 600                  * the first 2 items with special meaning, so we need
 601                  * to compensate for that by offsetting ourselves
 602                  */
 603                 if (device->brightness->flags._BCL_reversed)
 604                         bqc_value = device->brightness->count - 3 - bqc_value;
 605
 606                 level = device->brightness->levels[bqc_value + 2];
 607         } else {
 608                 level = bqc_value;
 609         }
 610
 611         level += bqc_offset_aml_bug_workaround;
 612
 613         return level;
 614 }
 615
 616 static int
 617 acpi_video_device_lcd_get_level_current(struct acpi_video_device *device,
 618                                         unsigned long long *level, bool raw)
 619 {
 620         acpi_status status = AE_OK;
 621         int i;
 622
 623         if (device->cap._BQC || device->cap._BCQ) {
 624                 char *buf = device->cap._BQC ? "_BQC" : "_BCQ";
 625
 626                 status = acpi_evaluate_integer(device->dev->handle, buf,
 627                                                 NULL, level);
 628                 if (ACPI_SUCCESS(status)) {
 629                         if (raw) {
 630                                 /*
 631                                  * Caller has indicated he wants the raw
 632                                  * value returned by _BQC, so don't furtherly
 633                                  * mess with the value.
 634                                  */
 635                                 return 0;
 636                         }
 637
 638                         *level = acpi_video_bqc_value_to_level(device, *level);
 639
 640                         for (i = 2; i < device->brightness->count; i++)
 641                                 if (device->brightness->levels[i] == *level) {
 642                                         device->brightness->curr = *level;
 643                                         return 0;
 644                                 }
 645                         /*
 646                          * BQC returned an invalid level.
 647                          * Stop using it.
 648                          */
 649                         ACPI_WARNING((AE_INFO,
 650                                       "%s returned an invalid level",
 651                                       buf));
 652                         device->cap._BQC = device->cap._BCQ = 0;
 653                 } else {
 654                         /*
 655                          * Fixme:
 656                          * should we return an error or ignore this failure?
 657                          * dev->brightness->curr is a cached value which stores
 658                          * the correct current backlight level in most cases.
 659                          * ACPI video backlight still works w/ buggy _BQC.
 660                          * http://bugzilla.kernel.org/show_bug.cgi?id=12233
 661                          */
 662                         ACPI_WARNING((AE_INFO, "Evaluating %s failed", buf));
 663                         device->cap._BQC = device->cap._BCQ = 0;
 664                 }
 665         }
 666
 667         *level = device->brightness->curr;
 668         return 0;
 669 }
 670
 671 static int
 672 acpi_video_device_EDID(struct acpi_video_device *device,
 673                        union acpi_object **edid, ssize_t length)
 674 {
 675         int status;
 676         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 677         union acpi_object *obj;
 678         union acpi_object arg0 = { ACPI_TYPE_INTEGER };
 679         struct acpi_object_list args = { 1, &arg0 };
 680
 681
 682         *edid = NULL;
 683
 684         if (!device)
 685                 return -ENODEV;
 686         if (length == 128)
 687                 arg0.integer.value = 1;
 688         else if (length == 256)
 689                 arg0.integer.value = 2;
 690         else
 691                 return -EINVAL;
 692
 693         status = acpi_evaluate_object(device->dev->handle, "_DDC", &args, &buffer);
 694         if (ACPI_FAILURE(status))
 695                 return -ENODEV;
 696
 697         obj = buffer.pointer;
 698
 699         if (obj && obj->type == ACPI_TYPE_BUFFER)
 700                 *edid = obj;
 701         else {
 702                 printk(KERN_ERR PREFIX "Invalid _DDC data\n");
 703                 status = -EFAULT;
 704                 kfree(obj);
 705         }
 706
 707         return status;
 708 }
 709
 710 /* bus */
 711
 712 /*
 713  *  Arg:
 714  *      video           : video bus device pointer
 715  *      bios_flag       :
 716  *              0.      The system BIOS should NOT automatically switch(toggle)
 717  *                      the active display output.
 718  *              1.      The system BIOS should automatically switch (toggle) the
 719  *                      active display output. No switch event.
 720  *              2.      The _DGS value should be locked.
 721  *              3.      The system BIOS should not automatically switch (toggle) the
 722  *                      active display output, but instead generate the display switch
 723  *                      event notify code.
 724  *      lcd_flag        :
 725  *              0.      The system BIOS should automatically control the brightness level
 726  *                      of the LCD when the power changes from AC to DC
 727  *              1.      The system BIOS should NOT automatically control the brightness
 728  *                      level of the LCD when the power changes from AC to DC.
 729  *  Return Value:
 730  *              -EINVAL wrong arg.
 731  */
 732
 733 static int
 734 acpi_video_bus_DOS(struct acpi_video_bus *video, int bios_flag, int lcd_flag)
 735 {
 736         acpi_status status;
 737
 738         if (!video->cap._DOS)
 739                 return 0;
 740
 741         if (bios_flag < 0 || bios_flag > 3 || lcd_flag < 0 || lcd_flag > 1)
 742                 return -EINVAL;
 743         video->dos_setting = (lcd_flag << 2) | bios_flag;
 744         status = acpi_execute_simple_method(video->device->handle, "_DOS",
 745                                             (lcd_flag << 2) | bios_flag);
 746         if (ACPI_FAILURE(status))
 747                 return -EIO;
 748
 749         return 0;
 750 }
 751
 752 /*
 753  * Simple comparison function used to sort backlight levels.
 754  */
 755
 756 static int
 757 acpi_video_cmp_level(const void *a, const void *b)
 758 {
 759         return *(int *)a - *(int *)b;
 760 }
 761
 762 /*
 763  * Decides if _BQC/_BCQ for this system is usable
 764  *
 765  * We do this by changing the level first and then read out the current
 766  * brightness level, if the value does not match, find out if it is using
 767  * index. If not, clear the _BQC/_BCQ capability.
 768  */
 769 static int acpi_video_bqc_quirk(struct acpi_video_device *device,
 770                                 int max_level, int current_level)
 771 {
 772         struct acpi_video_device_brightness *br = device->brightness;
 773         int result;
 774         unsigned long long level;
 775         int test_level;
 776
 777         /* don't mess with existing known broken systems */
 778         if (bqc_offset_aml_bug_workaround)
 779                 return 0;
 780
 781         /*
 782          * Some systems always report current brightness level as maximum
 783          * through _BQC, we need to test another value for them.
 784          */
 785         test_level = current_level == max_level ? br->levels[3] : max_level;
 786
 787         result = acpi_video_device_lcd_set_level(device, test_level);
 788         if (result)
 789                 return result;
 790
 791         result = acpi_video_device_lcd_get_level_current(device, &level, true);
 792         if (result)
 793                 return result;
 794
 795         if (level != test_level) {
 796                 /* buggy _BQC found, need to find out if it uses index */
 797                 if (level < br->count) {
 798                         if (br->flags._BCL_reversed)
 799                                 level = br->count - 3 - level;
 800                         if (br->levels[level + 2] == test_level)
 801                                 br->flags._BQC_use_index = 1;
 802                 }
 803
 804                 if (!br->flags._BQC_use_index)
 805                         device->cap._BQC = device->cap._BCQ = 0;
 806         }
 807
 808         return 0;
 809 }
 810
 811
 812 /*
 813  *  Arg:
 814  *      device  : video output device (LCD, CRT, ..)
 815  *
 816  *  Return Value:
 817  *      Maximum brightness level
 818  *
 819  *  Allocate and initialize device->brightness.
 820  */
 821
 822 static int
 823 acpi_video_init_brightness(struct acpi_video_device *device)
 824 {
 825         union acpi_object *obj = NULL;
 826         int i, max_level = 0, count = 0, level_ac_battery = 0;
 827         unsigned long long level, level_old;
 828         union acpi_object *o;
 829         struct acpi_video_device_brightness *br = NULL;
 830         int result = -EINVAL;
 831         u32 value;
 832
 833         if (!ACPI_SUCCESS(acpi_video_device_lcd_query_levels(device, &obj))) {
 834                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Could not query available "
 835                                                 "LCD brightness level\n"));
 836                 goto out;
 837         }
 838
 839         if (obj->package.count < 2)
 840                 goto out;
 841
 842         br = kzalloc(sizeof(*br), GFP_KERNEL);
 843         if (!br) {
 844                 printk(KERN_ERR "can't allocate memory\n");
 845                 result = -ENOMEM;
 846                 goto out;
 847         }
 848
 849         br->levels = kmalloc((obj->package.count + 2) * sizeof *(br->levels),
 850                                 GFP_KERNEL);
 851         if (!br->levels) {
 852                 result = -ENOMEM;
 853                 goto out_free;
 854         }
 855
 856         for (i = 0; i < obj->package.count; i++) {
 857                 o = (union acpi_object *)&obj->package.elements[i];
 858                 if (o->type != ACPI_TYPE_INTEGER) {
 859                         printk(KERN_ERR PREFIX "Invalid data\n");
 860                         continue;
 861                 }
 862                 value = (u32) o->integer.value;
 863                 /* Skip duplicate entries */
 864                 if (count > 2 && br->levels[count - 1] == value)
 865                         continue;
 866
 867                 br->levels[count] = value;
 868
 869                 if (br->levels[count] > max_level)
 870                         max_level = br->levels[count];
 871                 count++;
 872         }
 873
 874         /*
 875          * some buggy BIOS don't export the levels
 876          * when machine is on AC/Battery in _BCL package.
 877          * In this case, the first two elements in _BCL packages
 878          * are also supported brightness levels that OS should take care of.
 879          */
 880         for (i = 2; i < count; i++) {
 881                 if (br->levels[i] == br->levels[0])
 882                         level_ac_battery++;
 883                 if (br->levels[i] == br->levels[1])
 884                         level_ac_battery++;
 885         }
 886
 887         if (level_ac_battery < 2) {
 888                 level_ac_battery = 2 - level_ac_battery;
 889                 br->flags._BCL_no_ac_battery_levels = 1;
 890                 for (i = (count - 1 + level_ac_battery); i >= 2; i--)
 891                         br->levels[i] = br->levels[i - level_ac_battery];
 892                 count += level_ac_battery;
 893         } else if (level_ac_battery > 2)
 894                 ACPI_ERROR((AE_INFO, "Too many duplicates in _BCL package"));
 895
 896         /* Check if the _BCL package is in a reversed order */
 897         if (max_level == br->levels[2]) {
 898                 br->flags._BCL_reversed = 1;
 899                 sort(&br->levels[2], count - 2, sizeof(br->levels[2]),
 900                         acpi_video_cmp_level, NULL);
 901         } else if (max_level != br->levels[count - 1])
 902                 ACPI_ERROR((AE_INFO,
 903                             "Found unordered _BCL package"));
 904
 905         br->count = count;
 906         device->brightness = br;
 907
 908         /* _BQC uses INDEX while _BCL uses VALUE in some laptops */
 909         br->curr = level = max_level;
 910
 911         if (!device->cap._BQC)
 912                 goto set_level;
 913
 914         result = acpi_video_device_lcd_get_level_current(device,
 915                                                          &level_old, true);
 916         if (result)
 917                 goto out_free_levels;
 918
 919         result = acpi_video_bqc_quirk(device, max_level, level_old);
 920         if (result)
 921                 goto out_free_levels;
 922         /*
 923          * cap._BQC may get cleared due to _BQC is found to be broken
 924          * in acpi_video_bqc_quirk, so check again here.
 925          */
 926         if (!device->cap._BQC)
 927                 goto set_level;
 928
 929         level = acpi_video_bqc_value_to_level(device, level_old);
 930         /*
 931          * On some buggy laptops, _BQC returns an uninitialized
 932          * value when invoked for the first time, i.e.
 933          * level_old is invalid (no matter whether it's a level
 934          * or an index). Set the backlight to max_level in this case.
 935          */
 936         for (i = 2; i < br->count; i++)
 937                 if (level == br->levels[i])
 938                         break;
 939         if (i == br->count || !level)
 940                 level = max_level;
 941
 942 set_level:
 943         result = acpi_video_device_lcd_set_level(device, level);
 944         if (result)
 945                 goto out_free_levels;
 946
 947         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 948                           "found %d brightness levels\n", count - 2));
 949         kfree(obj);
 950         return result;
 951
 952 out_free_levels:
 953         kfree(br->levels);
 954 out_free:
 955         kfree(br);
 956 out:
 957         device->brightness = NULL;
 958         kfree(obj);
 959         return result;
 960 }
 961
 962 /*
 963  *  Arg:
 964  *      device  : video output device (LCD, CRT, ..)
 965  *
 966  *  Return Value:
 967  *      None
 968  *
 969  *  Find out all required AML methods defined under the output
 970  *  device.
 971  */
 972
 973 static void acpi_video_device_find_cap(struct acpi_video_device *device)
 974 {
 975         if (acpi_has_method(device->dev->handle, "_ADR"))
 976                 device->cap._ADR = 1;
 977         if (acpi_has_method(device->dev->handle, "_BCL"))
 978                 device->cap._BCL = 1;
 979         if (acpi_has_method(device->dev->handle, "_BCM"))
 980                 device->cap._BCM = 1;
 981         if (acpi_has_method(device->dev->handle, "_BQC")) {
 982                 device->cap._BQC = 1;
 983         } else if (acpi_has_method(device->dev->handle, "_BCQ")) {
 984                 printk(KERN_WARNING FW_BUG "_BCQ is used instead of _BQC\n");
 985                 device->cap._BCQ = 1;
 986         }
 987
 988         if (acpi_has_method(device->dev->handle, "_DDC"))
 989                 device->cap._DDC = 1;
 990 }
 991
 992 /*
 993  *  Arg:
 994  *      device  : video output device (VGA)
 995  *
 996  *  Return Value:
 997  *      None
 998  *
 999  *  Find out all required AML methods defined under the video bus device.
1000  */
1001
1002 static void acpi_video_bus_find_cap(struct acpi_video_bus *video)
1003 {
1004         if (acpi_has_method(video->device->handle, "_DOS"))
1005                 video->cap._DOS = 1;
1006         if (acpi_has_method(video->device->handle, "_DOD"))
1007                 video->cap._DOD = 1;
1008         if (acpi_has_method(video->device->handle, "_ROM"))
1009                 video->cap._ROM = 1;
1010         if (acpi_has_method(video->device->handle, "_GPD"))
1011                 video->cap._GPD = 1;
1012         if (acpi_has_method(video->device->handle, "_SPD"))
1013                 video->cap._SPD = 1;
1014         if (acpi_has_method(video->device->handle, "_VPO"))
1015                 video->cap._VPO = 1;
1016 }
1017
1018 /*
1019  * Check whether the video bus device has required AML method to
1020  * support the desired features
1021  */
1022
1023 static int acpi_video_bus_check(struct acpi_video_bus *video)
1024 {
1025         acpi_status status = -ENOENT;
1026         struct pci_dev *dev;
1027
1028         if (!video)
1029                 return -EINVAL;
1030
1031         dev = acpi_get_pci_dev(video->device->handle);
1032         if (!dev)
1033                 return -ENODEV;
1034         pci_dev_put(dev);
1035
1036         /*
1037          * Since there is no HID, CID and so on for VGA driver, we have
1038          * to check well known required nodes.
1039          */
1040
1041         /* Does this device support video switching? */
1042         if (video->cap._DOS || video->cap._DOD) {
1043                 if (!video->cap._DOS) {
1044                         printk(KERN_WARNING FW_BUG
1045                                 "ACPI(%s) defines _DOD but not _DOS\n",
1046                                 acpi_device_bid(video->device));
1047                 }
1048                 video->flags.multihead = 1;
1049                 status = 0;
1050         }
1051
1052         /* Does this device support retrieving a video ROM? */
1053         if (video->cap._ROM) {
1054                 video->flags.rom = 1;
1055                 status = 0;
1056         }
1057
1058         /* Does this device support configuring which video device to POST? */
1059         if (video->cap._GPD && video->cap._SPD && video->cap._VPO) {
1060                 video->flags.post = 1;
1061                 status = 0;
1062         }
1063
1064         return status;
1065 }
1066
1067 /*
1068  * --------------------------------------------------------------------------
1069  *                               Driver Interface
1070  * --------------------------------------------------------------------------
1071  */
1072
1073 /* device interface */
1074 static struct acpi_video_device_attrib *
1075 acpi_video_get_device_attr(struct acpi_video_bus *video, unsigned long device_id)
1076 {
1077         struct acpi_video_enumerated_device *ids;
1078         int i;
1079
1080         for (i = 0; i < video->attached_count; i++) {
1081                 ids = &video->attached_array[i];
1082                 if ((ids->value.int_val & 0xffff) == device_id)
1083                         return &ids->value.attrib;
1084         }
1085
1086         return NULL;
1087 }
1088
1089 static int
1090 acpi_video_get_device_type(struct acpi_video_bus *video,
1091                            unsigned long device_id)
1092 {
1093         struct acpi_video_enumerated_device *ids;
1094         int i;
1095
1096         for (i = 0; i < video->attached_count; i++) {
1097                 ids = &video->attached_array[i];
1098                 if ((ids->value.int_val & 0xffff) == device_id)
1099                         return ids->value.int_val;
1100         }
1101
1102         return 0;
1103 }
1104
1105 static int
1106 acpi_video_bus_get_one_device(struct acpi_device *device,
1107                               struct acpi_video_bus *video)
1108 {
1109         unsigned long long device_id;
1110         int status, device_type;
1111         struct acpi_video_device *data;
1112         struct acpi_video_device_attrib *attribute;
1113
1114         status =
1115             acpi_evaluate_integer(device->handle, "_ADR", NULL, &device_id);
1116         /* Some device omits _ADR, we skip them instead of fail */
1117         if (ACPI_FAILURE(status))
1118                 return 0;
1119
1120         data = kzalloc(sizeof(struct acpi_video_device), GFP_KERNEL);
1121         if (!data)
1122                 return -ENOMEM;
1123
1124         strcpy(acpi_device_name(device), ACPI_VIDEO_DEVICE_NAME);
1125         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1126         device->driver_data = data;
1127
1128         data->device_id = device_id;
1129         data->video = video;
1130         data->dev = device;
1131
1132         attribute = acpi_video_get_device_attr(video, device_id);
1133
1134         if (attribute && attribute->device_id_scheme) {
1135                 switch (attribute->display_type) {
1136                 case ACPI_VIDEO_DISPLAY_CRT:
1137                         data->flags.crt = 1;
1138                         break;
1139                 case ACPI_VIDEO_DISPLAY_TV:
1140                         data->flags.tvout = 1;
1141                         break;
1142                 case ACPI_VIDEO_DISPLAY_DVI:
1143                         data->flags.dvi = 1;
1144                         break;
1145                 case ACPI_VIDEO_DISPLAY_LCD:
1146                         data->flags.lcd = 1;
1147                         break;
1148                 default:
1149                         data->flags.unknown = 1;
1150                         break;
1151                 }
1152                 if (attribute->bios_can_detect)
1153                         data->flags.bios = 1;
1154         } else {
1155                 /* Check for legacy IDs */
1156                 device_type = acpi_video_get_device_type(video, device_id);
1157                 /* Ignore bits 16 and 18-20 */
1158                 switch (device_type & 0xffe2ffff) {
1159                 case ACPI_VIDEO_DISPLAY_LEGACY_MONITOR:
1160                         data->flags.crt = 1;
1161                         break;
1162                 case ACPI_VIDEO_DISPLAY_LEGACY_PANEL:
1163                         data->flags.lcd = 1;
1164                         break;
1165                 case ACPI_VIDEO_DISPLAY_LEGACY_TV:
1166                         data->flags.tvout = 1;
1167                         break;
1168                 default:
1169                         data->flags.unknown = 1;
1170                 }
1171         }
1172
1173         acpi_video_device_bind(video, data);
1174         acpi_video_device_find_cap(data);
1175
1176         mutex_lock(&video->device_list_lock);
1177         list_add_tail(&data->entry, &video->video_device_list);
1178         mutex_unlock(&video->device_list_lock);
1179
1180         return status;
1181 }
1182
1183 /*
1184  *  Arg:
1185  *      video   : video bus device
1186  *
1187  *  Return:
1188  *      none
1189  *
1190  *  Enumerate the video device list of the video bus,
1191  *  bind the ids with the corresponding video devices
1192  *  under the video bus.
1193  */
1194
1195 static void acpi_video_device_rebind(struct acpi_video_bus *video)
1196 {
1197         struct acpi_video_device *dev;
1198
1199         mutex_lock(&video->device_list_lock);
1200
1201         list_for_each_entry(dev, &video->video_device_list, entry)
1202                 acpi_video_device_bind(video, dev);
1203
1204         mutex_unlock(&video->device_list_lock);
1205 }
1206
1207 /*
1208  *  Arg:
1209  *      video   : video bus device
1210  *      device  : video output device under the video
1211  *              bus
1212  *
1213  *  Return:
1214  *      none
1215  *
1216  *  Bind the ids with the corresponding video devices
1217  *  under the video bus.
1218  */
1219
1220 static void
1221 acpi_video_device_bind(struct acpi_video_bus *video,
1222                        struct acpi_video_device *device)
1223 {
1224         struct acpi_video_enumerated_device *ids;
1225         int i;
1226
1227         for (i = 0; i < video->attached_count; i++) {
1228                 ids = &video->attached_array[i];
1229                 if (device->device_id == (ids->value.int_val & 0xffff)) {
1230                         ids->bind_info = device;
1231                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "device_bind %d\n", i));
1232                 }
1233         }
1234 }
1235
1236 /*
1237  *  Arg:
1238  *      video   : video bus device
1239  *
1240  *  Return:
1241  *      < 0     : error
1242  *
1243  *  Call _DOD to enumerate all devices attached to display adapter
1244  *
1245  */
1246
1247 static int acpi_video_device_enumerate(struct acpi_video_bus *video)
1248 {
1249         int status;
1250         int count;
1251         int i;
1252         struct acpi_video_enumerated_device *active_list;
1253         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
1254         union acpi_object *dod = NULL;
1255         union acpi_object *obj;
1256
1257         status = acpi_evaluate_object(video->device->handle, "_DOD", NULL, &buffer);
1258         if (!ACPI_SUCCESS(status)) {
1259                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _DOD"));
1260                 return status;
1261         }
1262
1263         dod = buffer.pointer;
1264         if (!dod || (dod->type != ACPI_TYPE_PACKAGE)) {
1265                 ACPI_EXCEPTION((AE_INFO, status, "Invalid _DOD data"));
1266                 status = -EFAULT;
1267                 goto out;
1268         }
1269
1270         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d video heads in _DOD\n",
1271                           dod->package.count));
1272
1273         active_list = kcalloc(1 + dod->package.count,
1274                               sizeof(struct acpi_video_enumerated_device),
1275                               GFP_KERNEL);
1276         if (!active_list) {
1277                 status = -ENOMEM;
1278                 goto out;
1279         }
1280
1281         count = 0;
1282         for (i = 0; i < dod->package.count; i++) {
1283                 obj = &dod->package.elements[i];
1284
1285                 if (obj->type != ACPI_TYPE_INTEGER) {
1286                         printk(KERN_ERR PREFIX
1287                                 "Invalid _DOD data in element %d\n", i);
1288                         continue;
1289                 }
1290
1291                 active_list[count].value.int_val = obj->integer.value;
1292                 active_list[count].bind_info = NULL;
1293                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "dod element[%d] = %d\n", i,
1294                                   (int)obj->integer.value));
1295                 count++;
1296         }
1297
1298         kfree(video->attached_array);
1299
1300         video->attached_array = active_list;
1301         video->attached_count = count;
1302
1303 out:
1304         kfree(buffer.pointer);
1305         return status;
1306 }
1307
1308 static int
1309 acpi_video_get_next_level(struct acpi_video_device *device,
1310                           u32 level_current, u32 event)
1311 {
1312         int min, max, min_above, max_below, i, l, delta = 255;
1313         max = max_below = 0;
1314         min = min_above = 255;
1315         /* Find closest level to level_current */
1316         for (i = 2; i < device->brightness->count; i++) {
1317                 l = device->brightness->levels[i];
1318                 if (abs(l - level_current) < abs(delta)) {
1319                         delta = l - level_current;
1320                         if (!delta)
1321                                 break;
1322                 }
1323         }
1324         /* Ajust level_current to closest available level */
1325         level_current += delta;
1326         for (i = 2; i < device->brightness->count; i++) {
1327                 l = device->brightness->levels[i];
1328                 if (l < min)
1329                         min = l;
1330                 if (l > max)
1331                         max = l;
1332                 if (l < min_above && l > level_current)
1333                         min_above = l;
1334                 if (l > max_below && l < level_current)
1335                         max_below = l;
1336         }
1337
1338         switch (event) {
1339         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:
1340                 return (level_current < max) ? min_above : min;
1341         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:
1342                 return (level_current < max) ? min_above : max;
1343         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:
1344                 return (level_current > min) ? max_below : min;
1345         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS:
1346         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:
1347                 return 0;
1348         default:
1349                 return level_current;
1350         }
1351 }
1352
1353 static int
1354 acpi_video_switch_brightness(struct acpi_video_device *device, int event)
1355 {
1356         unsigned long long level_current, level_next;
1357         int result = -EINVAL;
1358
1359         /* no warning message if acpi_backlight=vendor or a quirk is used */
1360         if (!acpi_video_verify_backlight_support())
1361                 return 0;
1362
1363         if (!device->brightness)
1364                 goto out;
1365
1366         result = acpi_video_device_lcd_get_level_current(device,
1367                                                          &level_current,
1368                                                          false);
1369         if (result)
1370                 goto out;
1371
1372         level_next = acpi_video_get_next_level(device, level_current, event);
1373
1374         result = acpi_video_device_lcd_set_level(device, level_next);
1375
1376         if (!result)
1377                 backlight_force_update(device->backlight,
1378                                        BACKLIGHT_UPDATE_HOTKEY);
1379
1380 out:
1381         if (result)
1382                 printk(KERN_ERR PREFIX "Failed to switch the brightness\n");
1383
1384         return result;
1385 }
1386
1387 int acpi_video_get_edid(struct acpi_device *device, int type, int device_id,
1388                         void **edid)
1389 {
1390         struct acpi_video_bus *video;
1391         struct acpi_video_device *video_device;
1392         union acpi_object *buffer = NULL;
1393         acpi_status status;
1394         int i, length;
1395
1396         if (!device || !acpi_driver_data(device))
1397                 return -EINVAL;
1398
1399         video = acpi_driver_data(device);
1400
1401         for (i = 0; i < video->attached_count; i++) {
1402                 video_device = video->attached_array[i].bind_info;
1403                 length = 256;
1404
1405                 if (!video_device)
1406                         continue;
1407
1408                 if (!video_device->cap._DDC)
1409                         continue;
1410
1411                 if (type) {
1412                         switch (type) {
1413                         case ACPI_VIDEO_DISPLAY_CRT:
1414                                 if (!video_device->flags.crt)
1415                                         continue;
1416                                 break;
1417                         case ACPI_VIDEO_DISPLAY_TV:
1418                                 if (!video_device->flags.tvout)
1419                                         continue;
1420                                 break;
1421                         case ACPI_VIDEO_DISPLAY_DVI:
1422                                 if (!video_device->flags.dvi)
1423                                         continue;
1424                                 break;
1425                         case ACPI_VIDEO_DISPLAY_LCD:
1426                                 if (!video_device->flags.lcd)
1427                                         continue;
1428                                 break;
1429                         }
1430                 } else if (video_device->device_id != device_id) {
1431                         continue;
1432                 }
1433
1434                 status = acpi_video_device_EDID(video_device, &buffer, length);
1435
1436                 if (ACPI_FAILURE(status) || !buffer ||
1437                     buffer->type != ACPI_TYPE_BUFFER) {
1438                         length = 128;
1439                         status = acpi_video_device_EDID(video_device, &buffer,
1440                                                         length);
1441                         if (ACPI_FAILURE(status) || !buffer ||
1442                             buffer->type != ACPI_TYPE_BUFFER) {
1443                                 continue;
1444                         }
1445                 }
1446
1447                 *edid = buffer->buffer.pointer;
1448                 return length;
1449         }
1450
1451         return -ENODEV;
1452 }
1453 EXPORT_SYMBOL(acpi_video_get_edid);
1454
1455 static int
1456 acpi_video_bus_get_devices(struct acpi_video_bus *video,
1457                            struct acpi_device *device)
1458 {
1459         int status = 0;
1460         struct acpi_device *dev;
1461
1462         /*
1463          * There are systems where video module known to work fine regardless
1464          * of broken _DOD and ignoring returned value here doesn't cause
1465          * any issues later.
1466          */
1467         acpi_video_device_enumerate(video);
1468
1469         list_for_each_entry(dev, &device->children, node) {
1470
1471                 status = acpi_video_bus_get_one_device(dev, video);
1472                 if (status) {
1473                         dev_err(&dev->dev, "Can't attach device\n");
1474                         break;
1475                 }
1476         }
1477         return status;
1478 }
1479
1480 /* acpi_video interface */
1481
1482 /*
1483  * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't
1484  * preform any automatic brightness change on receiving a notification.
1485  */
1486 static int acpi_video_bus_start_devices(struct acpi_video_bus *video)
1487 {
1488         return acpi_video_bus_DOS(video, 0,
1489                                   acpi_osi_is_win8() ? 1 : 0);
1490 }
1491
1492 static int acpi_video_bus_stop_devices(struct acpi_video_bus *video)
1493 {
1494         return acpi_video_bus_DOS(video, 0,
1495                                   acpi_osi_is_win8() ? 0 : 1);
1496 }
1497
1498 static void acpi_video_bus_notify(struct acpi_device *device, u32 event)
1499 {
1500         struct acpi_video_bus *video = acpi_driver_data(device);
1501         struct input_dev *input;
1502         int keycode = 0;
1503
1504         if (!video || !video->input)
1505                 return;
1506
1507         input = video->input;
1508
1509         switch (event) {
1510         case ACPI_VIDEO_NOTIFY_SWITCH:  /* User requested a switch,
1511                                          * most likely via hotkey. */
1512                 keycode = KEY_SWITCHVIDEOMODE;
1513                 break;
1514
1515         case ACPI_VIDEO_NOTIFY_PROBE:   /* User plugged in or removed a video
1516                                          * connector. */
1517                 acpi_video_device_enumerate(video);
1518                 acpi_video_device_rebind(video);
1519                 keycode = KEY_SWITCHVIDEOMODE;
1520                 break;
1521
1522         case ACPI_VIDEO_NOTIFY_CYCLE:   /* Cycle Display output hotkey pressed. */
1523                 keycode = KEY_SWITCHVIDEOMODE;
1524                 break;
1525         case ACPI_VIDEO_NOTIFY_NEXT_OUTPUT:     /* Next Display output hotkey pressed. */
1526                 keycode = KEY_VIDEO_NEXT;
1527                 break;
1528         case ACPI_VIDEO_NOTIFY_PREV_OUTPUT:     /* previous Display output hotkey pressed. */
1529                 keycode = KEY_VIDEO_PREV;
1530                 break;
1531
1532         default:
1533                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1534                                   "Unsupported event [0x%x]\n", event));
1535                 break;
1536         }
1537
1538         if (acpi_notifier_call_chain(device, event, 0))
1539                 /* Something vetoed the keypress. */
1540                 keycode = 0;
1541
1542         if (keycode) {
1543                 input_report_key(input, keycode, 1);
1544                 input_sync(input);
1545                 input_report_key(input, keycode, 0);
1546                 input_sync(input);
1547         }
1548
1549         return;
1550 }
1551
1552 static void acpi_video_device_notify(acpi_handle handle, u32 event, void *data)
1553 {
1554         struct acpi_video_device *video_device = data;
1555         struct acpi_device *device = NULL;
1556         struct acpi_video_bus *bus;
1557         struct input_dev *input;
1558         int keycode = 0;
1559
1560         if (!video_device)
1561                 return;
1562
1563         device = video_device->dev;
1564         bus = video_device->video;
1565         input = bus->input;
1566
1567         switch (event) {
1568         case ACPI_VIDEO_NOTIFY_CYCLE_BRIGHTNESS:        /* Cycle brightness */
1569                 if (brightness_switch_enabled)
1570                         acpi_video_switch_brightness(video_device, event);
1571                 keycode = KEY_BRIGHTNESS_CYCLE;
1572                 break;
1573         case ACPI_VIDEO_NOTIFY_INC_BRIGHTNESS:  /* Increase brightness */
1574                 if (brightness_switch_enabled)
1575                         acpi_video_switch_brightness(video_device, event);
1576                 keycode = KEY_BRIGHTNESSUP;
1577                 break;
1578         case ACPI_VIDEO_NOTIFY_DEC_BRIGHTNESS:  /* Decrease brightness */
1579                 if (brightness_switch_enabled)
1580                         acpi_video_switch_brightness(video_device, event);
1581                 keycode = KEY_BRIGHTNESSDOWN;
1582                 break;
1583         case ACPI_VIDEO_NOTIFY_ZERO_BRIGHTNESS: /* zero brightness */
1584                 if (brightness_switch_enabled)
1585                         acpi_video_switch_brightness(video_device, event);
1586                 keycode = KEY_BRIGHTNESS_ZERO;
1587                 break;
1588         case ACPI_VIDEO_NOTIFY_DISPLAY_OFF:     /* display device off */
1589                 if (brightness_switch_enabled)
1590                         acpi_video_switch_brightness(video_device, event);
1591                 keycode = KEY_DISPLAY_OFF;
1592                 break;
1593         default:
1594                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1595                                   "Unsupported event [0x%x]\n", event));
1596                 break;
1597         }
1598
1599         acpi_notifier_call_chain(device, event, 0);
1600
1601         if (keycode) {
1602                 input_report_key(input, keycode, 1);
1603                 input_sync(input);
1604                 input_report_key(input, keycode, 0);
1605                 input_sync(input);
1606         }
1607
1608         return;
1609 }
1610
1611 static int acpi_video_resume(struct notifier_block *nb,
1612                                 unsigned long val, void *ign)
1613 {
1614         struct acpi_video_bus *video;
1615         struct acpi_video_device *video_device;
1616         int i;
1617
1618         switch (val) {
1619         case PM_HIBERNATION_PREPARE:
1620         case PM_SUSPEND_PREPARE:
1621         case PM_RESTORE_PREPARE:
1622                 return NOTIFY_DONE;
1623         }
1624
1625         video = container_of(nb, struct acpi_video_bus, pm_nb);
1626
1627         dev_info(&video->device->dev, "Restoring backlight state\n");
1628
1629         for (i = 0; i < video->attached_count; i++) {
1630                 video_device = video->attached_array[i].bind_info;
1631                 if (video_device && video_device->backlight)
1632                         acpi_video_set_brightness(video_device->backlight);
1633         }
1634
1635         return NOTIFY_OK;
1636 }
1637
1638 static acpi_status
1639 acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
1640                         void **return_value)
1641 {
1642         struct acpi_device *device = context;
1643         struct acpi_device *sibling;
1644         int result;
1645
1646         if (handle == device->handle)
1647                 return AE_CTRL_TERMINATE;
1648
1649         result = acpi_bus_get_device(handle, &sibling);
1650         if (result)
1651                 return AE_OK;
1652
1653         if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
1654                         return AE_ALREADY_EXISTS;
1655
1656         return AE_OK;
1657 }
1658
1659 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
1660 {
1661         if (acpi_video_verify_backlight_support()) {
1662                 struct backlight_properties props;
1663                 struct pci_dev *pdev;
1664                 acpi_handle acpi_parent;
1665                 struct device *parent = NULL;
1666                 int result;
1667                 static int count;
1668                 char *name;
1669
1670                 result = acpi_video_init_brightness(device);
1671                 if (result)
1672                         return;
1673                 name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
1674                 if (!name)
1675                         return;
1676                 count++;
1677
1678                 acpi_get_parent(device->dev->handle, &acpi_parent);
1679
1680                 pdev = acpi_get_pci_dev(acpi_parent);
1681                 if (pdev) {
1682                         parent = &pdev->dev;
1683                         pci_dev_put(pdev);
1684                 }
1685
1686                 memset(&props, 0, sizeof(struct backlight_properties));
1687                 props.type = BACKLIGHT_FIRMWARE;
1688                 props.max_brightness = device->brightness->count - 3;
1689                 device->backlight = backlight_device_register(name,
1690                                                               parent,
1691                                                               device,
1692                                                               &acpi_backlight_ops,
1693                                                               &props);
1694                 kfree(name);
1695                 if (IS_ERR(device->backlight))
1696                         return;
1697
1698                 /*
1699                  * Save current brightness level in case we have to restore it
1700                  * before acpi_video_device_lcd_set_level() is called next time.
1701                  */
1702                 device->backlight->props.brightness =
1703                                 acpi_video_get_brightness(device->backlight);
1704
1705                 device->cooling_dev = thermal_cooling_device_register("LCD",
1706                                         device->dev, &video_cooling_ops);
1707                 if (IS_ERR(device->cooling_dev)) {
1708                         /*
1709                          * Set cooling_dev to NULL so we don't crash trying to
1710                          * free it.
1711                          * Also, why the hell we are returning early and
1712                          * not attempt to register video output if cooling
1713                          * device registration failed?
1714                          * -- dtor
1715                          */
1716                         device->cooling_dev = NULL;
1717                         return;
1718                 }
1719
1720                 dev_info(&device->dev->dev, "registered as cooling_device%d\n",
1721                          device->cooling_dev->id);
1722                 result = sysfs_create_link(&device->dev->dev.kobj,
1723                                 &device->cooling_dev->device.kobj,
1724                                 "thermal_cooling");
1725                 if (result)
1726                         printk(KERN_ERR PREFIX "Create sysfs link\n");
1727                 result = sysfs_create_link(&device->cooling_dev->device.kobj,
1728                                 &device->dev->dev.kobj, "device");
1729                 if (result)
1730                         printk(KERN_ERR PREFIX "Create sysfs link\n");
1731         }
1732 }
1733
1734 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
1735 {
1736         struct acpi_video_device *dev;
1737
1738         mutex_lock(&video->device_list_lock);
1739         list_for_each_entry(dev, &video->video_device_list, entry)
1740                 acpi_video_dev_register_backlight(dev);
1741         mutex_unlock(&video->device_list_lock);
1742
1743         video->pm_nb.notifier_call = acpi_video_resume;
1744         video->pm_nb.priority = 0;
1745         return register_pm_notifier(&video->pm_nb);
1746 }
1747
1748 static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device)
1749 {
1750         if (device->backlight) {
1751                 backlight_device_unregister(device->backlight);
1752                 device->backlight = NULL;
1753         }
1754         if (device->brightness) {
1755                 kfree(device->brightness->levels);
1756                 kfree(device->brightness);
1757                 device->brightness = NULL;
1758         }
1759         if (device->cooling_dev) {
1760                 sysfs_remove_link(&device->dev->dev.kobj, "thermal_cooling");
1761                 sysfs_remove_link(&device->cooling_dev->device.kobj, "device");
1762                 thermal_cooling_device_unregister(device->cooling_dev);
1763                 device->cooling_dev = NULL;
1764         }
1765 }
1766
1767 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
1768 {
1769         struct acpi_video_device *dev;
1770         int error = unregister_pm_notifier(&video->pm_nb);
1771
1772         mutex_lock(&video->device_list_lock);
1773         list_for_each_entry(dev, &video->video_device_list, entry)
1774                 acpi_video_dev_unregister_backlight(dev);
1775         mutex_unlock(&video->device_list_lock);
1776
1777         return error;
1778 }
1779
1780 static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
1781 {
1782         acpi_status status;
1783         struct acpi_device *adev = device->dev;
1784
1785         status = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
1786                                              acpi_video_device_notify, device);
1787         if (ACPI_FAILURE(status))
1788                 dev_err(&adev->dev, "Error installing notify handler\n");
1789         else
1790                 device->flags.notify = 1;
1791 }
1792
1793 static int acpi_video_bus_add_notify_handler(struct acpi_video_bus *video)
1794 {
1795         struct input_dev *input;
1796         struct acpi_video_device *dev;
1797         int error;
1798
1799         video->input = input = input_allocate_device();
1800         if (!input) {
1801                 error = -ENOMEM;
1802                 goto out;
1803         }
1804
1805         error = acpi_video_bus_start_devices(video);
1806         if (error)
1807                 goto err_free_input;
1808
1809         snprintf(video->phys, sizeof(video->phys),
1810                         "%s/video/input0", acpi_device_hid(video->device));
1811
1812         input->name = acpi_device_name(video->device);
1813         input->phys = video->phys;
1814         input->id.bustype = BUS_HOST;
1815         input->id.product = 0x06;
1816         input->dev.parent = &video->device->dev;
1817         input->evbit[0] = BIT(EV_KEY);
1818         set_bit(KEY_SWITCHVIDEOMODE, input->keybit);
1819         set_bit(KEY_VIDEO_NEXT, input->keybit);
1820         set_bit(KEY_VIDEO_PREV, input->keybit);
1821         set_bit(KEY_BRIGHTNESS_CYCLE, input->keybit);
1822         set_bit(KEY_BRIGHTNESSUP, input->keybit);
1823         set_bit(KEY_BRIGHTNESSDOWN, input->keybit);
1824         set_bit(KEY_BRIGHTNESS_ZERO, input->keybit);
1825         set_bit(KEY_DISPLAY_OFF, input->keybit);
1826
1827         error = input_register_device(input);
1828         if (error)
1829                 goto err_stop_dev;
1830
1831         mutex_lock(&video->device_list_lock);
1832         list_for_each_entry(dev, &video->video_device_list, entry)
1833                 acpi_video_dev_add_notify_handler(dev);
1834         mutex_unlock(&video->device_list_lock);
1835
1836         return 0;
1837
1838 err_stop_dev:
1839         acpi_video_bus_stop_devices(video);
1840 err_free_input:
1841         input_free_device(input);
1842         video->input = NULL;
1843 out:
1844         return error;
1845 }
1846
1847 static void acpi_video_dev_remove_notify_handler(struct acpi_video_device *dev)
1848 {
1849         if (dev->flags.notify) {
1850                 acpi_remove_notify_handler(dev->dev->handle, ACPI_DEVICE_NOTIFY,
1851                                            acpi_video_device_notify);
1852                 dev->flags.notify = 0;
1853         }
1854 }
1855
1856 static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video)
1857 {
1858         struct acpi_video_device *dev;
1859
1860         mutex_lock(&video->device_list_lock);
1861         list_for_each_entry(dev, &video->video_device_list, entry)
1862                 acpi_video_dev_remove_notify_handler(dev);
1863         mutex_unlock(&video->device_list_lock);
1864
1865         acpi_video_bus_stop_devices(video);
1866         input_unregister_device(video->input);
1867         video->input = NULL;
1868 }
1869
1870 static int acpi_video_bus_put_devices(struct acpi_video_bus *video)
1871 {
1872         struct acpi_video_device *dev, *next;
1873
1874         mutex_lock(&video->device_list_lock);
1875         list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
1876                 list_del(&dev->entry);
1877                 kfree(dev);
1878         }
1879         mutex_unlock(&video->device_list_lock);
1880
1881         return 0;
1882 }
1883
1884 static int instance;
1885
1886 static int acpi_video_bus_add(struct acpi_device *device)
1887 {
1888         struct acpi_video_bus *video;
1889         int error;
1890         acpi_status status;
1891
1892         status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
1893                                 device->parent->handle, 1,
1894                                 acpi_video_bus_match, NULL,
1895                                 device, NULL);
1896         if (status == AE_ALREADY_EXISTS) {
1897                 printk(KERN_WARNING FW_BUG
1898                         "Duplicate ACPI video bus devices for the"
1899                         " same VGA controller, please try module "
1900                         "parameter \"video.allow_duplicates=1\""
1901                         "if the current driver doesn't work.\n");
1902                 if (!allow_duplicates)
1903                         return -ENODEV;
1904         }
1905
1906         video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
1907         if (!video)
1908                 return -ENOMEM;
1909
1910         /* a hack to fix the duplicate name "VID" problem on T61 */
1911         if (!strcmp(device->pnp.bus_id, "VID")) {
1912                 if (instance)
1913                         device->pnp.bus_id[3] = '0' + instance;
1914                 instance++;
1915         }
1916         /* a hack to fix the duplicate name "VGA" problem on Pa 3553 */
1917         if (!strcmp(device->pnp.bus_id, "VGA")) {
1918                 if (instance)
1919                         device->pnp.bus_id[3] = '0' + instance;
1920                 instance++;
1921         }
1922
1923         video->device = device;
1924         strcpy(acpi_device_name(device), ACPI_VIDEO_BUS_NAME);
1925         strcpy(acpi_device_class(device), ACPI_VIDEO_CLASS);
1926         device->driver_data = video;
1927
1928         acpi_video_bus_find_cap(video);
1929         error = acpi_video_bus_check(video);
1930         if (error)
1931                 goto err_free_video;
1932
1933         mutex_init(&video->device_list_lock);
1934         INIT_LIST_HEAD(&video->video_device_list);
1935
1936         error = acpi_video_bus_get_devices(video, device);
1937         if (error)
1938                 goto err_put_video;
1939
1940         printk(KERN_INFO PREFIX "%s [%s] (multi-head: %s  rom: %s  post: %s)\n",
1941                ACPI_VIDEO_DEVICE_NAME, acpi_device_bid(device),
1942                video->flags.multihead ? "yes" : "no",
1943                video->flags.rom ? "yes" : "no",
1944                video->flags.post ? "yes" : "no");
1945         mutex_lock(&video_list_lock);
1946         list_add_tail(&video->entry, &video_bus_head);
1947         mutex_unlock(&video_list_lock);
1948
1949         acpi_video_bus_register_backlight(video);
1950         acpi_video_bus_add_notify_handler(video);
1951
1952         return 0;
1953
1954 err_put_video:
1955         acpi_video_bus_put_devices(video);
1956         kfree(video->attached_array);
1957 err_free_video:
1958         kfree(video);
1959         device->driver_data = NULL;
1960
1961         return error;
1962 }
1963
1964 static int acpi_video_bus_remove(struct acpi_device *device)
1965 {
1966         struct acpi_video_bus *video = NULL;
1967
1968
1969         if (!device || !acpi_driver_data(device))
1970                 return -EINVAL;
1971
1972         video = acpi_driver_data(device);
1973
1974         acpi_video_bus_remove_notify_handler(video);
1975         acpi_video_bus_unregister_backlight(video);
1976         acpi_video_bus_put_devices(video);
1977
1978         mutex_lock(&video_list_lock);
1979         list_del(&video->entry);
1980         mutex_unlock(&video_list_lock);
1981
1982         kfree(video->attached_array);
1983         kfree(video);
1984
1985         return 0;
1986 }
1987
1988 static int __init is_i740(struct pci_dev *dev)
1989 {
1990         if (dev->device == 0x00D1)
1991                 return 1;
1992         if (dev->device == 0x7000)
1993                 return 1;
1994         return 0;
1995 }
1996
1997 static int __init intel_opregion_present(void)
1998 {
1999         int opregion = 0;
2000         struct pci_dev *dev = NULL;
2001         u32 address;
2002
2003         for_each_pci_dev(dev) {
2004                 if ((dev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
2005                         continue;
2006                 if (dev->vendor != PCI_VENDOR_ID_INTEL)
2007                         continue;
2008                 /* We don't want to poke around undefined i740 registers */
2009                 if (is_i740(dev))
2010                         continue;
2011                 pci_read_config_dword(dev, 0xfc, &address);
2012                 if (!address)
2013                         continue;
2014                 opregion = 1;
2015         }
2016         return opregion;
2017 }
2018
2019 int acpi_video_register(void)
2020 {
2021         int result = 0;
2022         if (register_count) {
2023                 /*
2024                  * if the function of acpi_video_register is already called,
2025                  * don't register the acpi_vide_bus again and return no error.
2026                  */
2027                 return 0;
2028         }
2029
2030         mutex_init(&video_list_lock);
2031         INIT_LIST_HEAD(&video_bus_head);
2032
2033         result = acpi_bus_register_driver(&acpi_video_bus);
2034         if (result < 0)
2035                 return -ENODEV;
2036
2037         /*
2038          * When the acpi_video_bus is loaded successfully, increase
2039          * the counter reference.
2040          */
2041         register_count = 1;
2042
2043         return 0;
2044 }
2045 EXPORT_SYMBOL(acpi_video_register);
2046
2047 void acpi_video_unregister(void)
2048 {
2049         if (!register_count) {
2050                 /*
2051                  * If the acpi video bus is already unloaded, don't
2052                  * unload it again and return directly.
2053                  */
2054                 return;
2055         }
2056         acpi_bus_unregister_driver(&acpi_video_bus);
2057
2058         register_count = 0;
2059
2060         return;
2061 }
2062 EXPORT_SYMBOL(acpi_video_unregister);
2063
2064 /*
2065  * This is kind of nasty. Hardware using Intel chipsets may require
2066  * the video opregion code to be run first in order to initialise
2067  * state before any ACPI video calls are made. To handle this we defer
2068  * registration of the video class until the opregion code has run.
2069  */
2070
2071 static int __init acpi_video_init(void)
2072 {
2073         dmi_check_system(video_dmi_table);
2074
2075         if (intel_opregion_present())
2076                 return 0;
2077
2078         return acpi_video_register();
2079 }
2080
2081 static void __exit acpi_video_exit(void)
2082 {
2083         acpi_video_unregister();
2084
2085         return;
2086 }
2087
2088 module_init(acpi_video_init);
2089 module_exit(acpi_video_exit);