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 #include <linux/vgaarb.h>
  32
  33 struct vga_switcheroo_client {
  34         struct pci_dev *pdev;
  35         struct fb_info *fb_info;
  36         int pwr_state;
  37         const struct vga_switcheroo_client_ops *ops;
  38         int id;
  39         bool active;
  40         struct list_head list;
  41 };
  42
  43 static DEFINE_MUTEX(vgasr_mutex);
  44
  45 struct vgasr_priv {
  46
  47         bool active;
  48         bool delayed_switch_active;
  49         enum vga_switcheroo_client_id delayed_client_id;
  50
  51         struct dentry *debugfs_root;
  52         struct dentry *switch_file;
  53
  54         int registered_clients;
  55         struct list_head clients;
  56
  57         struct vga_switcheroo_handler *handler;
  58 };
  59
  60 #define ID_BIT_AUDIO            0x100
  61 #define client_is_audio(c)      ((c)->id & ID_BIT_AUDIO)
  62 #define client_is_vga(c)        ((c)->id == -1 || !client_is_audio(c))
  63 #define client_id(c)            ((c)->id & ~ID_BIT_AUDIO)
  64
  65 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv);
  66 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv);
  67
  68 /* only one switcheroo per system */
  69 static struct vgasr_priv vgasr_priv = {
  70         .clients = LIST_HEAD_INIT(vgasr_priv.clients),
  71 };
  72
  73 int vga_switcheroo_register_handler(struct vga_switcheroo_handler *handler)
  74 {
  75         mutex_lock(&vgasr_mutex);
  76         if (vgasr_priv.handler) {
  77                 mutex_unlock(&vgasr_mutex);
  78                 return -EINVAL;
  79         }
  80
  81         vgasr_priv.handler = handler;
  82         mutex_unlock(&vgasr_mutex);
  83         return 0;
  84 }
  85 EXPORT_SYMBOL(vga_switcheroo_register_handler);
  86
  87 void vga_switcheroo_unregister_handler(void)
  88 {
  89         mutex_lock(&vgasr_mutex);
  90         vgasr_priv.handler = NULL;
  91         mutex_unlock(&vgasr_mutex);
  92 }
  93 EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
  94
  95 static void vga_switcheroo_enable(void)
  96 {
  97         int ret;
  98         struct vga_switcheroo_client *client;
  99
 100         /* call the handler to init */
 101         vgasr_priv.handler->init();
 102
 103         list_for_each_entry(client, &vgasr_priv.clients, list) {
 104                 if (client->id != -1)
 105                         continue;
 106                 ret = vgasr_priv.handler->get_client_id(client->pdev);
 107                 if (ret < 0)
 108                         return;
 109
 110                 client->id = ret;
 111         }
 112         vga_switcheroo_debugfs_init(&vgasr_priv);
 113         vgasr_priv.active = true;
 114 }
 115
 116 static int register_client(struct pci_dev *pdev,
 117                            const struct vga_switcheroo_client_ops *ops,
 118                            int id, bool active)
 119 {
 120         struct vga_switcheroo_client *client;
 121
 122         client = kzalloc(sizeof(*client), GFP_KERNEL);
 123         if (!client)
 124                 return -ENOMEM;
 125
 126         client->pwr_state = VGA_SWITCHEROO_ON;
 127         client->pdev = pdev;
 128         client->ops = ops;
 129         client->id = id;
 130         client->active = active;
 131
 132         mutex_lock(&vgasr_mutex);
 133         list_add_tail(&client->list, &vgasr_priv.clients);
 134         if (client_is_vga(client))
 135                 vgasr_priv.registered_clients++;
 136
 137         /* if we get two clients + handler */
 138         if (!vgasr_priv.active &&
 139             vgasr_priv.registered_clients == 2 && vgasr_priv.handler) {
 140                 printk(KERN_INFO "vga_switcheroo: enabled\n");
 141                 vga_switcheroo_enable();
 142         }
 143         mutex_unlock(&vgasr_mutex);
 144         return 0;
 145 }
 146
 147 int vga_switcheroo_register_client(struct pci_dev *pdev,
 148                                    const struct vga_switcheroo_client_ops *ops)
 149 {
 150         return register_client(pdev, ops, -1,
 151                                pdev == vga_default_device());
 152 }
 153 EXPORT_SYMBOL(vga_switcheroo_register_client);
 154
 155 int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
 156                                          const struct vga_switcheroo_client_ops *ops,
 157                                          int id, bool active)
 158 {
 159         return register_client(pdev, ops, id | ID_BIT_AUDIO, active);
 160 }
 161 EXPORT_SYMBOL(vga_switcheroo_register_audio_client);
 162
 163 static struct vga_switcheroo_client *
 164 find_client_from_pci(struct list_head *head, struct pci_dev *pdev)
 165 {
 166         struct vga_switcheroo_client *client;
 167         list_for_each_entry(client, head, list)
 168                 if (client->pdev == pdev)
 169                         return client;
 170         return NULL;
 171 }
 172
 173 static struct vga_switcheroo_client *
 174 find_client_from_id(struct list_head *head, int client_id)
 175 {
 176         struct vga_switcheroo_client *client;
 177         list_for_each_entry(client, head, list)
 178                 if (client->id == client_id)
 179                         return client;
 180         return NULL;
 181 }
 182
 183 static struct vga_switcheroo_client *
 184 find_active_client(struct list_head *head)
 185 {
 186         struct vga_switcheroo_client *client;
 187         list_for_each_entry(client, head, list)
 188                 if (client->active && client_is_vga(client))
 189                         return client;
 190         return NULL;
 191 }
 192
 193 void vga_switcheroo_unregister_client(struct pci_dev *pdev)
 194 {
 195         struct vga_switcheroo_client *client;
 196
 197         mutex_lock(&vgasr_mutex);
 198         client = find_client_from_pci(&vgasr_priv.clients, pdev);
 199         if (client) {
 200                 if (client_is_vga(client))
 201                         vgasr_priv.registered_clients--;
 202                 list_del(&client->list);
 203                 kfree(client);
 204         }
 205         if (vgasr_priv.active && vgasr_priv.registered_clients < 2) {
 206                 printk(KERN_INFO "vga_switcheroo: disabled\n");
 207                 vga_switcheroo_debugfs_fini(&vgasr_priv);
 208                 vgasr_priv.active = false;
 209         }
 210         mutex_unlock(&vgasr_mutex);
 211 }
 212 EXPORT_SYMBOL(vga_switcheroo_unregister_client);
 213
 214 void vga_switcheroo_client_fb_set(struct pci_dev *pdev,
 215                                  struct fb_info *info)
 216 {
 217         struct vga_switcheroo_client *client;
 218
 219         mutex_lock(&vgasr_mutex);
 220         client = find_client_from_pci(&vgasr_priv.clients, pdev);
 221         if (client)
 222                 client->fb_info = info;
 223         mutex_unlock(&vgasr_mutex);
 224 }
 225 EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
 226
 227 static int vga_switcheroo_show(struct seq_file *m, void *v)
 228 {
 229         struct vga_switcheroo_client *client;
 230         int i = 0;
 231         mutex_lock(&vgasr_mutex);
 232         list_for_each_entry(client, &vgasr_priv.clients, list) {
 233                 seq_printf(m, "%d:%s%s:%c:%s:%s\n", i,
 234                            client_id(client) == VGA_SWITCHEROO_DIS ? "DIS" : "IGD",
 235                            client_is_vga(client) ? "" : "-Audio",
 236                            client->active ? '+' : ' ',
 237                            client->pwr_state ? "Pwr" : "Off",
 238                            pci_name(client->pdev));
 239                 i++;
 240         }
 241         mutex_unlock(&vgasr_mutex);
 242         return 0;
 243 }
 244
 245 static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file)
 246 {
 247         return single_open(file, vga_switcheroo_show, NULL);
 248 }
 249
 250 static int vga_switchon(struct vga_switcheroo_client *client)
 251 {
 252         if (vgasr_priv.handler->power_state)
 253                 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_ON);
 254         /* call the driver callback to turn on device */
 255         client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_ON);
 256         client->pwr_state = VGA_SWITCHEROO_ON;
 257         return 0;
 258 }
 259
 260 static int vga_switchoff(struct vga_switcheroo_client *client)
 261 {
 262         /* call the driver callback to turn off device */
 263         client->ops->set_gpu_state(client->pdev, VGA_SWITCHEROO_OFF);
 264         if (vgasr_priv.handler->power_state)
 265                 vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF);
 266         client->pwr_state = VGA_SWITCHEROO_OFF;
 267         return 0;
 268 }
 269
 270 static void set_audio_state(int id, int state)
 271 {
 272         struct vga_switcheroo_client *client;
 273
 274         client = find_client_from_id(&vgasr_priv.clients, id | ID_BIT_AUDIO);
 275         if (client && client->pwr_state != state) {
 276                 client->ops->set_gpu_state(client->pdev, state);
 277                 client->pwr_state = state;
 278         }
 279 }
 280
 281 /* stage one happens before delay */
 282 static int vga_switchto_stage1(struct vga_switcheroo_client *new_client)
 283 {
 284         struct vga_switcheroo_client *active;
 285
 286         active = find_active_client(&vgasr_priv.clients);
 287         if (!active)
 288                 return 0;
 289
 290         if (new_client->pwr_state == VGA_SWITCHEROO_OFF)
 291                 vga_switchon(new_client);
 292
 293         vga_set_default_device(new_client->pdev);
 294         set_audio_state(new_client->id, VGA_SWITCHEROO_ON);
 295
 296         return 0;
 297 }
 298
 299 /* post delay */
 300 static int vga_switchto_stage2(struct vga_switcheroo_client *new_client)
 301 {
 302         int ret;
 303         struct vga_switcheroo_client *active;
 304
 305         active = find_active_client(&vgasr_priv.clients);
 306         if (!active)
 307                 return 0;
 308
 309         active->active = false;
 310
 311         if (new_client->fb_info) {
 312                 struct fb_event event;
 313                 event.info = new_client->fb_info;
 314                 fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE, &event);
 315         }
 316
 317         ret = vgasr_priv.handler->switchto(new_client->id);
 318         if (ret)
 319                 return ret;
 320
 321         if (new_client->ops->reprobe)
 322                 new_client->ops->reprobe(new_client->pdev);
 323
 324         set_audio_state(active->id, VGA_SWITCHEROO_OFF);
 325
 326         if (active->pwr_state == VGA_SWITCHEROO_ON)
 327                 vga_switchoff(active);
 328
 329         new_client->active = true;
 330         return 0;
 331 }
 332
 333 static bool check_can_switch(void)
 334 {
 335         struct vga_switcheroo_client *client;
 336
 337         list_for_each_entry(client, &vgasr_priv.clients, list) {
 338                 if (!client->ops->can_switch(client->pdev)) {
 339                         printk(KERN_ERR "vga_switcheroo: client %x refused switch\n", client->id);
 340                         return false;
 341                 }
 342         }
 343         return true;
 344 }
 345
 346 static ssize_t
 347 vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
 348                              size_t cnt, loff_t *ppos)
 349 {
 350         char usercmd[64];
 351         const char *pdev_name;
 352         int ret;
 353         bool delay = false, can_switch;
 354         bool just_mux = false;
 355         int client_id = -1;
 356         struct vga_switcheroo_client *client = NULL;
 357
 358         if (cnt > 63)
 359                 cnt = 63;
 360
 361         if (copy_from_user(usercmd, ubuf, cnt))
 362                 return -EFAULT;
 363
 364         mutex_lock(&vgasr_mutex);
 365
 366         if (!vgasr_priv.active) {
 367                 cnt = -EINVAL;
 368                 goto out;
 369         }
 370
 371         /* pwr off the device not in use */
 372         if (strncmp(usercmd, "OFF", 3) == 0) {
 373                 list_for_each_entry(client, &vgasr_priv.clients, list) {
 374                         if (client->active)
 375                                 continue;
 376                         if (client->pwr_state == VGA_SWITCHEROO_ON)
 377                                 vga_switchoff(client);
 378                 }
 379                 goto out;
 380         }
 381         /* pwr on the device not in use */
 382         if (strncmp(usercmd, "ON", 2) == 0) {
 383                 list_for_each_entry(client, &vgasr_priv.clients, list) {
 384                         if (client->active)
 385                                 continue;
 386                         if (client->pwr_state == VGA_SWITCHEROO_OFF)
 387                                 vga_switchon(client);
 388                 }
 389                 goto out;
 390         }
 391
 392         /* request a delayed switch - test can we switch now */
 393         if (strncmp(usercmd, "DIGD", 4) == 0) {
 394                 client_id = VGA_SWITCHEROO_IGD;
 395                 delay = true;
 396         }
 397
 398         if (strncmp(usercmd, "DDIS", 4) == 0) {
 399                 client_id = VGA_SWITCHEROO_DIS;
 400                 delay = true;
 401         }
 402
 403         if (strncmp(usercmd, "IGD", 3) == 0)
 404                 client_id = VGA_SWITCHEROO_IGD;
 405
 406         if (strncmp(usercmd, "DIS", 3) == 0)
 407                 client_id = VGA_SWITCHEROO_DIS;
 408
 409         if (strncmp(usercmd, "MIGD", 4) == 0) {
 410                 just_mux = true;
 411                 client_id = VGA_SWITCHEROO_IGD;
 412         }
 413         if (strncmp(usercmd, "MDIS", 4) == 0) {
 414                 just_mux = true;
 415                 client_id = VGA_SWITCHEROO_DIS;
 416         }
 417
 418         if (client_id == -1)
 419                 goto out;
 420         client = find_client_from_id(&vgasr_priv.clients, client_id);
 421         if (!client)
 422                 goto out;
 423
 424         vgasr_priv.delayed_switch_active = false;
 425
 426         if (just_mux) {
 427                 ret = vgasr_priv.handler->switchto(client_id);
 428                 goto out;
 429         }
 430
 431         if (client->active)
 432                 goto out;
 433
 434         /* okay we want a switch - test if devices are willing to switch */
 435         can_switch = check_can_switch();
 436
 437         if (can_switch == false && delay == false)
 438                 goto out;
 439
 440         if (can_switch) {
 441                 pdev_name = pci_name(client->pdev);
 442                 ret = vga_switchto_stage1(client);
 443                 if (ret)
 444                         printk(KERN_ERR "vga_switcheroo: switching failed stage 1 %d\n", ret);
 445
 446                 ret = vga_switchto_stage2(client);
 447                 if (ret)
 448                         printk(KERN_ERR "vga_switcheroo: switching failed stage 2 %d\n", ret);
 449
 450         } else {
 451                 printk(KERN_INFO "vga_switcheroo: setting delayed switch to client %d\n", client->id);
 452                 vgasr_priv.delayed_switch_active = true;
 453                 vgasr_priv.delayed_client_id = client_id;
 454
 455                 ret = vga_switchto_stage1(client);
 456                 if (ret)
 457                         printk(KERN_ERR "vga_switcheroo: delayed switching stage 1 failed %d\n", ret);
 458         }
 459
 460 out:
 461         mutex_unlock(&vgasr_mutex);
 462         return cnt;
 463 }
 464
 465 static const struct file_operations vga_switcheroo_debugfs_fops = {
 466         .owner = THIS_MODULE,
 467         .open = vga_switcheroo_debugfs_open,
 468         .write = vga_switcheroo_debugfs_write,
 469         .read = seq_read,
 470         .llseek = seq_lseek,
 471         .release = single_release,
 472 };
 473
 474 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv)
 475 {
 476         if (priv->switch_file) {
 477                 debugfs_remove(priv->switch_file);
 478                 priv->switch_file = NULL;
 479         }
 480         if (priv->debugfs_root) {
 481                 debugfs_remove(priv->debugfs_root);
 482                 priv->debugfs_root = NULL;
 483         }
 484 }
 485
 486 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv)
 487 {
 488         /* already initialised */
 489         if (priv->debugfs_root)
 490                 return 0;
 491         priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);
 492
 493         if (!priv->debugfs_root) {
 494                 printk(KERN_ERR "vga_switcheroo: Cannot create /sys/kernel/debug/vgaswitcheroo\n");
 495                 goto fail;
 496         }
 497
 498         priv->switch_file = debugfs_create_file("switch", 0644,
 499                                                 priv->debugfs_root, NULL, &vga_switcheroo_debugfs_fops);
 500         if (!priv->switch_file) {
 501                 printk(KERN_ERR "vga_switcheroo: cannot create /sys/kernel/debug/vgaswitcheroo/switch\n");
 502                 goto fail;
 503         }
 504         return 0;
 505 fail:
 506         vga_switcheroo_debugfs_fini(priv);
 507         return -1;
 508 }
 509
 510 int vga_switcheroo_process_delayed_switch(void)
 511 {
 512         struct vga_switcheroo_client *client;
 513         const char *pdev_name;
 514         int ret;
 515         int err = -EINVAL;
 516
 517         mutex_lock(&vgasr_mutex);
 518         if (!vgasr_priv.delayed_switch_active)
 519                 goto err;
 520
 521         printk(KERN_INFO "vga_switcheroo: processing delayed switch to %d\n", vgasr_priv.delayed_client_id);
 522
 523         client = find_client_from_id(&vgasr_priv.clients,
 524                                      vgasr_priv.delayed_client_id);
 525         if (!client || !check_can_switch())
 526                 goto err;
 527
 528         pdev_name = pci_name(client->pdev);
 529         ret = vga_switchto_stage2(client);
 530         if (ret)
 531                 printk(KERN_ERR "vga_switcheroo: delayed switching failed stage 2 %d\n", ret);
 532
 533         vgasr_priv.delayed_switch_active = false;
 534         err = 0;
 535 err:
 536         mutex_unlock(&vgasr_mutex);
 537         return err;
 538 }
 539 EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);
 540