drivers/acpi/video_detect.c

   1 /*
   2  *  Copyright (C) 2008       SuSE Linux Products GmbH
   3  *                           Thomas Renninger <trenn@suse.de>
   4  *
   5  *  May be copied or modified under the terms of the GNU General Public License
   6  *
   7  * video_detect.c:
   8  * Provides acpi_is_video_device() for early scanning of ACPI devices in scan.c
   9  * There a Linux specific (Spec does not provide a HID for video devices) is
  10  * assinged
  11  *
  12  * After PCI devices are glued with ACPI devices
  13  * acpi_get_physical_pci_device() can be called to identify ACPI graphics
  14  * devices for which a real graphics card is plugged in
  15  *
  16  * Now acpi_video_get_capabilities() can be called to check which
  17  * capabilities the graphics cards plugged in support. The check for general
  18  * video capabilities will be triggered by the first caller of
  19  * acpi_video_get_capabilities(NULL); which will happen when the first
  20  * backlight (or display output) switching supporting driver calls:
  21  * acpi_video_backlight_support();
  22  *
  23  * Depending on whether ACPI graphics extensions (cmp. ACPI spec Appendix B)
  24  * are available, video.ko should be used to handle the device.
  25  *
  26  * Otherwise vendor specific drivers like thinkpad_acpi, asus_acpi,
  27  * sony_acpi,... can take care about backlight brightness and display output
  28  * switching.
  29  *
  30  * If CONFIG_ACPI_VIDEO is neither set as "compiled in" (y) nor as a module (m)
  31  * this file will not be compiled, acpi_video_get_capabilities() and
  32  * acpi_video_backlight_support() will always return 0 and vendor specific
  33  * drivers always can handle backlight.
  34  *
  35  */
  36
  37 #include <linux/acpi.h>
  38 #include <linux/dmi.h>
  39
  40 ACPI_MODULE_NAME("video");
  41 #define _COMPONENT              ACPI_VIDEO_COMPONENT
  42
  43 static long acpi_video_support;
  44 static bool acpi_video_caps_checked;
  45
  46 static acpi_status
  47 acpi_backlight_cap_match(acpi_handle handle, u32 level, void *context,
  48                           void **retyurn_value)
  49 {
  50         long *cap = context;
  51         acpi_handle h_dummy;
  52
  53         if (ACPI_SUCCESS(acpi_get_handle(handle, "_BCM", &h_dummy)) &&
  54             ACPI_SUCCESS(acpi_get_handle(handle, "_BCL", &h_dummy))) {
  55                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found generic backlight "
  56                                   "support\n"));
  57                 *cap |= ACPI_VIDEO_BACKLIGHT;
  58                 if (ACPI_FAILURE(acpi_get_handle(handle, "_BQC", &h_dummy)))
  59                         printk(KERN_WARNING FW_BUG PREFIX "ACPI brightness "
  60                                         "control misses _BQC function\n");
  61                 /* We have backlight support, no need to scan further */
  62                 return AE_CTRL_TERMINATE;
  63         }
  64         return 0;
  65 }
  66
  67 /* Returns true if the device is a video device which can be handled by
  68  * video.ko.
  69  * The device will get a Linux specific CID added in scan.c to
  70  * identify the device as an ACPI graphics device
  71  * Be aware that the graphics device may not be physically present
  72  * Use acpi_video_get_capabilities() to detect general ACPI video
  73  * capabilities of present cards
  74  */
  75 long acpi_is_video_device(struct acpi_device *device)
  76 {
  77         acpi_handle h_dummy;
  78         long video_caps = 0;
  79
  80         if (!device)
  81                 return 0;
  82
  83         /* Does this device able to support video switching ? */
  84         if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOD", &h_dummy)) &&
  85             ACPI_SUCCESS(acpi_get_handle(device->handle, "_DOS", &h_dummy)))
  86                 video_caps |= ACPI_VIDEO_OUTPUT_SWITCHING;
  87
  88         /* Does this device able to retrieve a video ROM ? */
  89         if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_ROM", &h_dummy)))
  90                 video_caps |= ACPI_VIDEO_ROM_AVAILABLE;
  91
  92         /* Does this device able to configure which video head to be POSTed ? */
  93         if (ACPI_SUCCESS(acpi_get_handle(device->handle, "_VPO", &h_dummy)) &&
  94             ACPI_SUCCESS(acpi_get_handle(device->handle, "_GPD", &h_dummy)) &&
  95             ACPI_SUCCESS(acpi_get_handle(device->handle, "_SPD", &h_dummy)))
  96                 video_caps |= ACPI_VIDEO_DEVICE_POSTING;
  97
  98         /* Only check for backlight functionality if one of the above hit. */
  99         if (video_caps)
 100                 acpi_walk_namespace(ACPI_TYPE_DEVICE, device->handle,
 101                                     ACPI_UINT32_MAX, acpi_backlight_cap_match,
 102                                     &video_caps, NULL);
 103
 104         return video_caps;
 105 }
 106 EXPORT_SYMBOL(acpi_is_video_device);
 107
 108 static acpi_status
 109 find_video(acpi_handle handle, u32 lvl, void *context, void **rv)
 110 {
 111         long *cap = context;
 112         struct device *dev;
 113         struct acpi_device *acpi_dev;
 114
 115         const struct acpi_device_id video_ids[] = {
 116                 {ACPI_VIDEO_HID, 0},
 117                 {"", 0},
 118         };
 119         if (acpi_bus_get_device(handle, &acpi_dev))
 120                 return AE_OK;
 121
 122         if (!acpi_match_device_ids(acpi_dev, video_ids)) {
 123                 dev = acpi_get_physical_pci_device(handle);
 124                 if (!dev)
 125                         return AE_OK;
 126                 put_device(dev);
 127                 *cap |= acpi_is_video_device(acpi_dev);
 128         }
 129         return AE_OK;
 130 }
 131
 132 /*
 133  * Returns the video capabilities of a specific ACPI graphics device
 134  *
 135  * if NULL is passed as argument all ACPI devices are enumerated and
 136  * all graphics capabilities of physically present devices are
 137  * summerized and returned. This is cached and done only once.
 138  */
 139 long acpi_video_get_capabilities(acpi_handle graphics_handle)
 140 {
 141         long caps = 0;
 142         struct acpi_device *tmp_dev;
 143         acpi_status status;
 144
 145         if (acpi_video_caps_checked && graphics_handle == NULL)
 146                 return acpi_video_support;
 147
 148         if (!graphics_handle) {
 149                 /* Only do the global walk through all graphics devices once */
 150                 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 151                                     ACPI_UINT32_MAX, find_video,
 152                                     &caps, NULL);
 153                 /* There might be boot param flags set already... */
 154                 acpi_video_support |= caps;
 155                 acpi_video_caps_checked = 1;
 156                 /* Add blacklists here. Be careful to use the right *DMI* bits
 157                  * to still be able to override logic via boot params, e.g.:
 158                  *
 159                  *   if (dmi_name_in_vendors("XY")) {
 160                  *      acpi_video_support |=
 161                  *              ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR;
 162                  *      acpi_video_support |=
 163                  *              ACPI_VIDEO_BACKLIGHT_DMI_VENDOR;
 164                  *}
 165                  */
 166         } else {
 167                 status = acpi_bus_get_device(graphics_handle, &tmp_dev);
 168                 if (ACPI_FAILURE(status)) {
 169                         ACPI_EXCEPTION((AE_INFO, status, "Invalid device"));
 170                         return 0;
 171                 }
 172                 acpi_walk_namespace(ACPI_TYPE_DEVICE, graphics_handle,
 173                                     ACPI_UINT32_MAX, find_video,
 174                                     &caps, NULL);
 175         }
 176         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "We have 0x%lX video support %s %s\n",
 177                           graphics_handle ? caps : acpi_video_support,
 178                           graphics_handle ? "on device " : "in general",
 179                           graphics_handle ? acpi_device_bid(tmp_dev) : ""));
 180         return caps;
 181 }
 182 EXPORT_SYMBOL(acpi_video_get_capabilities);
 183
 184 /* Returns true if video.ko can do backlight switching */
 185 int acpi_video_backlight_support(void)
 186 {
 187         /*
 188          * We must check whether the ACPI graphics device is physically plugged
 189          * in. Therefore this must be called after binding PCI and ACPI devices
 190          */
 191         if (!acpi_video_caps_checked)
 192                 acpi_video_get_capabilities(NULL);
 193
 194         /* First check for boot param -> highest prio */
 195         if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR)
 196                 return 0;
 197         else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO)
 198                 return 1;
 199
 200         /* Then check for DMI blacklist -> second highest prio */
 201         if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VENDOR)
 202                 return 0;
 203         else if (acpi_video_support & ACPI_VIDEO_BACKLIGHT_DMI_VIDEO)
 204                 return 1;
 205
 206         /* Then go the default way */
 207         return acpi_video_support & ACPI_VIDEO_BACKLIGHT;
 208 }
 209 EXPORT_SYMBOL(acpi_video_backlight_support);
 210
 211 /*
 212  * Returns true if video.ko can do display output switching.
 213  * This does not work well/at all with binary graphics drivers
 214  * which disable system io ranges and do it on their own.
 215  */
 216 int acpi_video_display_switch_support(void)
 217 {
 218         if (!acpi_video_caps_checked)
 219                 acpi_video_get_capabilities(NULL);
 220
 221         if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR)
 222                 return 0;
 223         else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO)
 224                 return 1;
 225
 226         if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VENDOR)
 227                 return 0;
 228         else if (acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING_DMI_VIDEO)
 229                 return 1;
 230
 231         return acpi_video_support & ACPI_VIDEO_OUTPUT_SWITCHING;
 232 }
 233 EXPORT_SYMBOL(acpi_video_display_switch_support);
 234
 235 /*
 236  * Use acpi_display_output=vendor/video or acpi_backlight=vendor/video
 237  * To force that backlight or display output switching is processed by vendor
 238  * specific acpi drivers or video.ko driver.
 239  */
 240 static int __init acpi_backlight(char *str)
 241 {
 242         if (str == NULL || *str == '\0')
 243                 return 1;
 244         else {
 245                 if (!strcmp("vendor", str))
 246                         acpi_video_support |=
 247                                 ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR;
 248                 if (!strcmp("video", str))
 249                         acpi_video_support |=
 250                                 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO;
 251         }
 252         return 1;
 253 }
 254 __setup("acpi_backlight=", acpi_backlight);
 255
 256 static int __init acpi_display_output(char *str)
 257 {
 258         if (str == NULL || *str == '\0')
 259                 return 1;
 260         else {
 261                 if (!strcmp("vendor", str))
 262                         acpi_video_support |=
 263                                 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VENDOR;
 264                 if (!strcmp("video", str))
 265                         acpi_video_support |=
 266                                 ACPI_VIDEO_OUTPUT_SWITCHING_FORCE_VIDEO;
 267         }
 268         return 1;
 269 }
 270 __setup("acpi_display_output=", acpi_display_output);