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