drivers/gpu/vga/vga_switcheroo.c

   1 /*
   2  * Copyright (c) 2010 Red Hat Inc.
   3  * Author : Dave Airlie <airlied@redhat.com>
   4  *
   5  *
   6  * Licensed under GPLv2
   7  *
   8  * vga_switcheroo.c - Support for laptop with dual GPU using one set of outputs
   9
  10  Switcher interface - methods require for ATPX and DCM
  11  - switchto - this throws the output MUX switch
  12  - discrete_set_power - sets the power state for the discrete card
  13
  14  GPU driver interface
  15  - set_gpu_state - this should do the equiv of s/r for the card
  16                   - this should *not* set the discrete power state
  17  - switch_check  - check if the device is in a position to switch now
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/dmi.h>
  22 #include <linux/seq_file.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/fs.h>
  25 #include <linux/debugfs.h>
  26 #include <linux/fb.h>
  27
  28 #include <linux/pci.h>
  29 #include <linux/vga_switcheroo.h>
  30
  31 struct vga_switcheroo_client {
  32         struct pci_dev *pdev;
  33         struct fb_info *fb_info;
  34         int pwr_state;
  35         void (*set_gpu_state)(struct pci_dev *pdev, enum vga_switcheroo_state);
  36         void (*reprobe)(struct pci_dev *pdev);
  37         bool (*can_switch)(struct pci_dev *pdev);
  38         int id;
  39         bool active;
  40 };
  41
  42 static DEFINE_MUTEX(vgasr_mutex);
  43
  44 struct vgasr_priv {
  45
  46         bool active;
  47         bool delayed_switch_active;
  48         enum vga_switcheroo_client_id delayed_client_id;
  49
  50         struct dentry *debugfs_root;
  51         struct dentry *switch_file;
  52
  53         int registered_clients;
  54         struct vga_switcheroo_client clients[VGA_SWITCHEROO_MAX_CLIENTS];
  55
  56         struct vga_switcheroo_handler *handler;
  57 };
  58
  59 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv);
  60 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv);
  61
  62 /* only one switcheroo per system */
  63 static struct vgasr_priv vgasr_priv;
  64
  65 int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler)
  66 {
  67         mutex_lock(&vgasr_mutex);
  68         if (vgasr_priv.handler) {
  69                 mutex_unlock(&vgasr_mutex);
  70                 return -EINVAL;
  71         }
  72
  73         vgasr_priv.handler = handler;
  74         mutex_unlock(&vgasr_mutex);
  75         return 0;
  76 }
  77 EXPORT_SYMBOL(vga_switcheroo_register_handler);
  78
  79 void vga_switcheroo_unregister_handler(void)
  80 {
  81         mutex_lock(&vgasr_mutex);
  82         vgasr_priv.handler = NULL;
  83         mutex_unlock(&vgasr_mutex);
  84 }
  85 EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
  86
  87 static void vga_switcheroo_enable(void)
  88 {
  89         int i;
  90         int ret;
  91         /* call the handler to init */
  92         vgasr_priv.handler->init();
  93
  94         for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
  95                 ret = vgasr_priv.handler->get_client_id(vgasr_priv.clients[i].pdev);
  96                 if (ret < 0)
  97                         return;
  98
  99                 vgasr_priv.clients[i].id = ret;
 100         }
 101         vga_switcheroo_debugfs_init(&vgasr_priv);
 102         vgasr_priv.active = true;
 103 }
 104
 105 int vga_switcheroo_register_client(struct pci_dev *pdev,
 106                                    void (*set_gpu_state)(struct pci_dev *pdev, enum vga_switcheroo_state),
 107                                    void (*reprobe)(struct pci_dev *pdev),
 108                                    bool (*can_switch)(struct pci_dev *pdev))
 109 {
 110         int index;
 111
 112         mutex_lock(&vgasr_mutex);
 113         /* don't do IGD vs DIS here */
 114         if (vgasr_priv.registered_clients & 1)
 115                 index = 1;
 116         else
 117                 index = 0;
 118
 119         vgasr_priv.clients[index].pwr_state = VGA_SWITCHEROO_ON;
 120         vgasr_priv.clients[index].pdev = pdev;
 121         vgasr_priv.clients[index].set_gpu_state = set_gpu_state;
 122         vgasr_priv.clients[index].reprobe = reprobe;
 123         vgasr_priv.clients[index].can_switch = can_switch;
 124         vgasr_priv.clients[index].id = -1;
 125         if (pdev->resource[PCI_ROM_RESOURCE].flags & IORESOURCE_ROM_SHADOW)
 126                 vgasr_priv.clients[index].active = true;
 127
 128         vgasr_priv.registered_clients |= (1 << index);
 129
 130         /* if we get two clients + handler */
 131         if (vgasr_priv.registered_clients == 0x3 && vgasr_priv.handler) {
 132                 printk(KERN_INFO "vga_switcheroo: enabled\n");
 133                 vga_switcheroo_enable();
 134         }
 135         mutex_unlock(&vgasr_mutex);
 136         return 0;
 137 }
 138 EXPORT_SYMBOL(vga_switcheroo_register_client);
 139
 140 void vga_switcheroo_unregister_client(struct pci_dev *pdev)
 141 {
 142         int i;
 143
 144         mutex_lock(&vgasr_mutex);
 145         for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
 146                 if (vgasr_priv.clients[i].pdev == pdev) {
 147                         vgasr_priv.registered_clients &= ~(1 << i);
 148                         break;
 149                 }
 150         }
 151
 152         printk(KERN_INFO "vga_switcheroo: disabled\n");
 153         vga_switcheroo_debugfs_fini(&vgasr_priv);
 154         vgasr_priv.active = false;
 155         mutex_unlock(&vgasr_mutex);
 156 }
 157 EXPORT_SYMBOL(vga_switcheroo_unregister_client);
 158
 159 void vga_switcheroo_client_fb_set(struct pci_dev *pdev,
 160                                  struct fb_info *info)
 161 {
 162         int i;
 163
 164         mutex_lock(&vgasr_mutex);
 165         for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
 166                 if (vgasr_priv.clients[i].pdev == pdev) {
 167                         vgasr_priv.clients[i].fb_info = info;
 168                         break;
 169                 }
 170         }
 171         mutex_unlock(&vgasr_mutex);
 172 }
 173 EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
 174
 175 static int vga_switcheroo_show(struct seq_file *m, void *v)
 176 {
 177         int i;
 178         mutex_lock(&vgasr_mutex);
 179         for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
 180                 seq_printf(m, "%d:%s:%c:%s:%s\n", i,
 181                            vgasr_priv.clients[i].id == VGA_SWITCHEROO_DIS ? "DIS" : "IGD",
 182                            vgasr_priv.clients[i].active ? '+' : ' ',
 183                            vgasr_priv.clients[i].pwr_state ? "Pwr" : "Off",
 184                            pci_name(vgasr_priv.clients[i].pdev));
 185         }
 186         mutex_unlock(&vgasr_mutex);
 187         return 0;
 188 }
 189
 190 static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file)
 191 {
 192         return single_open(file, vga_switcheroo_show, NULL);
 193 }
 194
 195 static int vga_switchon(struct vga_switcheroo_client *client)
 196 {
 197         if (vgasr_priv.handler->power_state)
 198                 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_ON);
 199         /* call the driver callback to turn on device */
 200         client->set_gpu_state(client->pdev, VGA_SWITCHEROO_ON);
 201         client->pwr_state = VGA_SWITCHEROO_ON;
 202         return 0;
 203 }
 204
 205 static int vga_switchoff(struct vga_switcheroo_client *client)
 206 {
 207         /* call the driver callback to turn off device */
 208         client->set_gpu_state(client->pdev, VGA_SWITCHEROO_OFF);
 209         if (vgasr_priv.handler->power_state)
 210                 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF);
 211         client->pwr_state = VGA_SWITCHEROO_OFF;
 212         return 0;
 213 }
 214
 215 /* stage one happens before delay */
 216 static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
 217 {
 218         int i;
 219         struct vga_switcheroo_client *active = NULL;
 220
 221         for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
 222                 if (vgasr_priv.clients[i].active == true) {
 223                         active = &vgasr_priv.clients[i];
 224                         break;
 225                 }
 226         }
 227         if (!active)
 228                 return 0;
 229
 230         if (new_client->pwr_state == VGA_SWITCHEROO_OFF)
 231                 vga_switchon(new_client);
 232
 233         /* swap shadow resource to denote boot VGA device has changed so X starts on new device */
 234         active->pdev->resource[PCI_ROM_RESOURCE].flags &= ~IORESOURCE_ROM_SHADOW;
 235         new_client->pdev->resource[PCI_ROM_RESOURCE].flags |= IORESOURCE_ROM_SHADOW;
 236         return 0;
 237 }
 238
 239 /* post delay */
 240 static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
 241 {
 242         int ret;
 243         int i;
 244         struct vga_switcheroo_client *active = NULL;
 245
 246         for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
 247                 if (vgasr_priv.clients[i].active == true) {
 248                         active = &vgasr_priv.clients[i];
 249                         break;
 250                 }
 251         }
 252         if (!active)
 253                 return 0;
 254
 255         active->active = false;
 256
 257         if (new_client->fb_info) {
 258                 struct fb_event event;
 259                 event.info = new_client->fb_info;
 260                 fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE, &event);
 261         }
 262
 263         ret = vgasr_priv.handler->switchto(new_client->id);
 264         if (ret)
 265                 return ret;
 266
 267         if (new_client->reprobe)
 268                 new_client->reprobe(new_client->pdev);
 269
 270         if (active->pwr_state == VGA_SWITCHEROO_ON)
 271                 vga_switchoff(active);
 272
 273         new_client->active = true;
 274         return 0;
 275 }
 276
 277 static ssize_t
 278 vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
 279                              size_t cnt, loff_t *ppos)
 280 {
 281         char usercmd[64];
 282         const char *pdev_name;
 283         int i, ret;
 284         bool delay = false, can_switch;
 285         bool just_mux = false;
 286         int client_id = -1;
 287         struct vga_switcheroo_client *client = NULL;
 288
 289         if (cnt > 63)
 290                 cnt = 63;
 291
 292         if (copy_from_user(usercmd, ubuf, cnt))
 293                 return -EFAULT;
 294
 295         mutex_lock(&vgasr_mutex);
 296
 297         if (!vgasr_priv.active) {
 298                 cnt = -EINVAL;
 299                 goto out;
 300         }
 301
 302         /* pwr off the device not in use */
 303         if (strncmp(usercmd, "OFF", 3) == 0) {
 304                 for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
 305                         if (vgasr_priv.clients[i].active)
 306                                 continue;
 307                         if (vgasr_priv.clients[i].pwr_state == VGA_SWITCHEROO_ON)
 308                                 vga_switchoff(&vgasr_priv.clients[i]);
 309                 }
 310                 goto out;
 311         }
 312         /* pwr on the device not in use */
 313         if (strncmp(usercmd, "ON", 2) == 0) {
 314                 for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
 315                         if (vgasr_priv.clients[i].active)
 316                                 continue;
 317                         if (vgasr_priv.clients[i].pwr_state == VGA_SWITCHEROO_OFF)
 318                                 vga_switchon(&vgasr_priv.clients[i]);
 319                 }
 320                 goto out;
 321         }
 322
 323         /* request a delayed switch - test can we switch now */
 324         if (strncmp(usercmd, "DIGD", 4) == 0) {
 325                 client_id = VGA_SWITCHEROO_IGD;
 326                 delay = true;
 327         }
 328
 329         if (strncmp(usercmd, "DDIS", 4) == 0) {
 330                 client_id = VGA_SWITCHEROO_DIS;
 331                 delay = true;
 332         }
 333
 334         if (strncmp(usercmd, "IGD", 3) == 0)
 335                 client_id = VGA_SWITCHEROO_IGD;
 336
 337         if (strncmp(usercmd, "DIS", 3) == 0)
 338                 client_id = VGA_SWITCHEROO_DIS;
 339
 340         if (strncmp(usercmd, "MIGD", 4) == 0) {
 341                 just_mux = true;
 342                 client_id = VGA_SWITCHEROO_IGD;
 343         }
 344         if (strncmp(usercmd, "MDIS", 4) == 0) {
 345                 just_mux = true;
 346                 client_id = VGA_SWITCHEROO_DIS;
 347         }
 348
 349         if (client_id == -1)
 350                 goto out;
 351
 352         for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
 353                 if (vgasr_priv.clients[i].id == client_id) {
 354                         client = &vgasr_priv.clients[i];
 355                         break;
 356                 }
 357         }
 358
 359         vgasr_priv.delayed_switch_active = false;
 360
 361         if (just_mux) {
 362                 ret = vgasr_priv.handler->switchto(client_id);
 363                 goto out;
 364         }
 365
 366         if (client->active == true)
 367                 goto out;
 368
 369         /* okay we want a switch - test if devices are willing to switch */
 370         can_switch = true;
 371         for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
 372                 can_switch = vgasr_priv.clients[i].can_switch(vgasr_priv.clients[i].pdev);
 373                 if (can_switch == false) {
 374                         printk(KERN_ERR "vga_switcheroo: client %d refused switch\n", i);
 375                         break;
 376                 }
 377         }
 378
 379         if (can_switch == false && delay == false)
 380                 goto out;
 381
 382         if (can_switch == true) {
 383                 pdev_name = pci_name(client->pdev);
 384                 ret = vga_switchto_stage1(client);
 385                 if (ret)
 386                         printk(KERN_ERR "vga_switcheroo: switching failed stage 1 %d\n", ret);
 387
 388                 ret = vga_switchto_stage2(client);
 389                 if (ret)
 390                         printk(KERN_ERR "vga_switcheroo: switching failed stage 2 %d\n", ret);
 391
 392         } else {
 393                 printk(KERN_INFO "vga_switcheroo: setting delayed switch to client %d\n", client->id);
 394                 vgasr_priv.delayed_switch_active = true;
 395                 vgasr_priv.delayed_client_id = client_id;
 396
 397                 ret = vga_switchto_stage1(client);
 398                 if (ret)
 399                         printk(KERN_ERR "vga_switcheroo: delayed switching stage 1 failed %d\n", ret);
 400         }
 401
 402 out:
 403         mutex_unlock(&vgasr_mutex);
 404         return cnt;
 405 }
 406
 407 static const struct file_operations vga_switcheroo_debugfs_fops = {
 408         .owner = THIS_MODULE,
 409         .open = vga_switcheroo_debugfs_open,
 410         .write = vga_switcheroo_debugfs_write,
 411         .read = seq_read,
 412         .llseek = seq_lseek,
 413         .release = single_release,
 414 };
 415
 416 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv)
 417 {
 418         if (priv->switch_file) {
 419                 debugfs_remove(priv->switch_file);
 420                 priv->switch_file = NULL;
 421         }
 422         if (priv->debugfs_root) {
 423                 debugfs_remove(priv->debugfs_root);
 424                 priv->debugfs_root = NULL;
 425         }
 426 }
 427
 428 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv)
 429 {
 430         /* already initialised */
 431         if (priv->debugfs_root)
 432                 return 0;
 433         priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);
 434
 435         if (!priv->debugfs_root) {
 436                 printk(KERN_ERR "vga_switcheroo: Cannot create /sys/kernel/debug/vgaswitcheroo\n");
 437                 goto fail;
 438         }
 439
 440         priv->switch_file = debugfs_create_file("switch", 0644,
 441                                                 priv->debugfs_root, NULL, &vga_switcheroo_debugfs_fops);
 442         if (!priv->switch_file) {
 443                 printk(KERN_ERR "vga_switcheroo: cannot create /sys/kernel/debug/vgaswitcheroo/switch\n");
 444                 goto fail;
 445         }
 446         return 0;
 447 fail:
 448         vga_switcheroo_debugfs_fini(priv);
 449         return -1;
 450 }
 451
 452 int vga_switcheroo_process_delayed_switch(void)
 453 {
 454         struct vga_switcheroo_client *client = NULL;
 455         const char *pdev_name;
 456         bool can_switch = true;
 457         int i;
 458         int ret;
 459         int err = -EINVAL;
 460
 461         mutex_lock(&vgasr_mutex);
 462         if (!vgasr_priv.delayed_switch_active)
 463                 goto err;
 464
 465         printk(KERN_INFO "vga_switcheroo: processing delayed switch to %d\n", vgasr_priv.delayed_client_id);
 466
 467         for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
 468                 if (vgasr_priv.clients[i].id == vgasr_priv.delayed_client_id)
 469                         client = &vgasr_priv.clients[i];
 470                 can_switch = vgasr_priv.clients[i].can_switch(vgasr_priv.clients[i].pdev);
 471                 if (can_switch == false) {
 472                         printk(KERN_ERR "vga_switcheroo: client %d refused switch\n", i);
 473                         break;
 474                 }
 475         }
 476
 477         if (can_switch == false || client == NULL)
 478                 goto err;
 479
 480         pdev_name = pci_name(client->pdev);
 481         ret = vga_switchto_stage2(client);
 482         if (ret)
 483                 printk(KERN_ERR "vga_switcheroo: delayed switching failed stage 2 %d\n", ret);
 484
 485         vgasr_priv.delayed_switch_active = false;
 486         err = 0;
 487 err:
 488         mutex_unlock(&vgasr_mutex);
 489         return err;
 490 }
 491 EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);
 492