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:%c:%s:%s\n", i,
 178                            vgasr_priv.clients[i].active ? '+' : ' ',
 179                            vgasr_priv.clients[i].pwr_state ? "Pwr" : "Off",
 180                            pci_name(vgasr_priv.clients[i].pdev));
 181         }
 182         mutex_unlock(&vgasr_mutex);
 183         return 0;
 184 }
 185
 186 static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file)
 187 {
 188         return single_open(file, vga_switcheroo_show, NULL);
 189 }
 190
 191 static int vga_switchon(struct vga_switcheroo_client *client)
 192 {
 193         int ret;
 194
 195         ret = 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         vgasr_priv.handler->power_state(client->id, VGA_SWITCHEROO_OFF);
 207         client->pwr_state = VGA_SWITCHEROO_OFF;
 208         return 0;
 209 }
 210
 211 static int vga_switchto(struct vga_switcheroo_client *new_client)
 212 {
 213         int ret;
 214         int i;
 215         struct vga_switcheroo_client *active = NULL;
 216
 217         if (new_client->active == true)
 218                 return 0;
 219
 220         for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
 221                 if (vgasr_priv.clients[i].active == true) {
 222                         active = &vgasr_priv.clients[i];
 223                         break;
 224                 }
 225         }
 226         if (!active)
 227                 return 0;
 228
 229         /* power up the first device */
 230         ret = pci_enable_device(new_client->pdev);
 231         if (ret)
 232                 return ret;
 233
 234         if (new_client->pwr_state == VGA_SWITCHEROO_OFF)
 235                 vga_switchon(new_client);
 236
 237         /* swap shadow resource to denote boot VGA device has changed so X starts on new device */
 238         active->active = false;
 239
 240         active->pdev->resource[PCI_ROM_RESOURCE].flags &= ~IORESOURCE_ROM_SHADOW;
 241         new_client->pdev->resource[PCI_ROM_RESOURCE].flags |= IORESOURCE_ROM_SHADOW;
 242
 243         if (new_client->fb_info) {
 244                 struct fb_event event;
 245                 event.info = new_client->fb_info;
 246                 fb_notifier_call_chain(FB_EVENT_REMAP_ALL_CONSOLE, &event);
 247         }
 248
 249         ret = vgasr_priv.handler->switchto(new_client->id);
 250         if (ret)
 251                 return ret;
 252
 253         if (active->pwr_state == VGA_SWITCHEROO_ON)
 254                 vga_switchoff(active);
 255
 256         new_client->active = true;
 257         return 0;
 258 }
 259
 260 static ssize_t
 261 vga_switcheroo_debugfs_write(struct file *filp, const char __user *ubuf,
 262                              size_t cnt, loff_t *ppos)
 263 {
 264         char usercmd[64];
 265         const char *pdev_name;
 266         int i, ret;
 267         bool delay = false, can_switch;
 268         int client_id = -1;
 269         struct vga_switcheroo_client *client = NULL;
 270
 271         if (cnt > 63)
 272                 cnt = 63;
 273
 274         if (copy_from_user(usercmd, ubuf, cnt))
 275                 return -EFAULT;
 276
 277         mutex_lock(&vgasr_mutex);
 278
 279         if (!vgasr_priv.active) {
 280                 cnt = -EINVAL;
 281                 goto out;
 282         }
 283
 284         /* pwr off the device not in use */
 285         if (strncmp(usercmd, "OFF", 3) == 0) {
 286                 for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
 287                         if (vgasr_priv.clients[i].active)
 288                                 continue;
 289                         if (vgasr_priv.clients[i].pwr_state == VGA_SWITCHEROO_ON)
 290                                 vga_switchoff(&vgasr_priv.clients[i]);
 291                 }
 292                 goto out;
 293         }
 294         /* pwr on the device not in use */
 295         if (strncmp(usercmd, "ON", 2) == 0) {
 296                 for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
 297                         if (vgasr_priv.clients[i].active)
 298                                 continue;
 299                         if (vgasr_priv.clients[i].pwr_state == VGA_SWITCHEROO_OFF)
 300                                 vga_switchon(&vgasr_priv.clients[i]);
 301                 }
 302                 goto out;
 303         }
 304
 305         /* request a delayed switch - test can we switch now */
 306         if (strncmp(usercmd, "DIGD", 4) == 0) {
 307                 client_id = VGA_SWITCHEROO_IGD;
 308                 delay = true;
 309         }
 310
 311         if (strncmp(usercmd, "DDIS", 4) == 0) {
 312                 client_id = VGA_SWITCHEROO_DIS;
 313                 delay = true;
 314         }
 315
 316         if (strncmp(usercmd, "IGD", 3) == 0)
 317                 client_id = VGA_SWITCHEROO_IGD;
 318
 319         if (strncmp(usercmd, "DIS", 3) == 0)
 320                 client_id = VGA_SWITCHEROO_DIS;
 321
 322         if (client_id == -1)
 323                 goto out;
 324
 325         for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
 326                 if (vgasr_priv.clients[i].id == client_id) {
 327                         client = &vgasr_priv.clients[i];
 328                         break;
 329                 }
 330         }
 331
 332         vgasr_priv.delayed_switch_active = false;
 333         /* okay we want a switch - test if devices are willing to switch */
 334         can_switch = true;
 335         for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
 336                 can_switch = vgasr_priv.clients[i].can_switch(vgasr_priv.clients[i].pdev);
 337                 if (can_switch == false) {
 338                         printk(KERN_ERR "vga_switcheroo: client %d refused switch\n", i);
 339                         break;
 340                 }
 341         }
 342
 343         if (can_switch == false && delay == false)
 344                 goto out;
 345
 346         if (can_switch == true) {
 347                 pdev_name = pci_name(client->pdev);
 348                 ret = vga_switchto(client);
 349                 if (ret)
 350                         printk(KERN_ERR "vga_switcheroo: switching failed %d\n", ret);
 351         } else {
 352                 printk(KERN_INFO "vga_switcheroo: setting delayed switch to client %d\n", client->id);
 353                 vgasr_priv.delayed_switch_active = true;
 354                 vgasr_priv.delayed_client_id = client_id;
 355
 356                 /* we should at least power up the card to
 357                    make the switch faster */
 358                 if (client->pwr_state == VGA_SWITCHEROO_OFF)
 359                         vga_switchon(client);
 360         }
 361
 362 out:
 363         mutex_unlock(&vgasr_mutex);
 364         return cnt;
 365 }
 366
 367 static const struct file_operations vga_switcheroo_debugfs_fops = {
 368         .owner = THIS_MODULE,
 369         .open = vga_switcheroo_debugfs_open,
 370         .write = vga_switcheroo_debugfs_write,
 371         .read = seq_read,
 372         .llseek = seq_lseek,
 373         .release = single_release,
 374 };
 375
 376 static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv)
 377 {
 378         if (priv->switch_file) {
 379                 debugfs_remove(priv->switch_file);
 380                 priv->switch_file = NULL;
 381         }
 382         if (priv->debugfs_root) {
 383                 debugfs_remove(priv->debugfs_root);
 384                 priv->debugfs_root = NULL;
 385         }
 386 }
 387
 388 static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv)
 389 {
 390         /* already initialised */
 391         if (priv->debugfs_root)
 392                 return 0;
 393         priv->debugfs_root = debugfs_create_dir("vgaswitcheroo", NULL);
 394
 395         if (!priv->debugfs_root) {
 396                 printk(KERN_ERR "vga_switcheroo: Cannot create /sys/kernel/debug/vgaswitcheroo\n");
 397                 goto fail;
 398         }
 399
 400         priv->switch_file = debugfs_create_file("switch", 0644,
 401                                                 priv->debugfs_root, NULL, &vga_switcheroo_debugfs_fops);
 402         if (!priv->switch_file) {
 403                 printk(KERN_ERR "vga_switcheroo: cannot create /sys/kernel/debug/vgaswitcheroo/switch\n");
 404                 goto fail;
 405         }
 406         return 0;
 407 fail:
 408         vga_switcheroo_debugfs_fini(priv);
 409         return -1;
 410 }
 411
 412 int vga_switcheroo_process_delayed_switch(void)
 413 {
 414         struct vga_switcheroo_client *client = NULL;
 415         const char *pdev_name;
 416         bool can_switch = true;
 417         int i;
 418         int ret;
 419         int err = -EINVAL;
 420
 421         mutex_lock(&vgasr_mutex);
 422         if (!vgasr_priv.delayed_switch_active)
 423                 goto err;
 424
 425         printk(KERN_INFO "vga_switcheroo: processing delayed switch to %d\n", vgasr_priv.delayed_client_id);
 426
 427         for (i = 0; i < VGA_SWITCHEROO_MAX_CLIENTS; i++) {
 428                 if (vgasr_priv.clients[i].id == vgasr_priv.delayed_client_id)
 429                         client = &vgasr_priv.clients[i];
 430                 can_switch = vgasr_priv.clients[i].can_switch(vgasr_priv.clients[i].pdev);
 431                 if (can_switch == false) {
 432                         printk(KERN_ERR "vga_switcheroo: client %d refused switch\n", i);
 433                         break;
 434                 }
 435         }
 436
 437         if (can_switch == false || client == NULL)
 438                 goto err;
 439
 440         pdev_name = pci_name(client->pdev);
 441         ret = vga_switchto(client);
 442         if (ret)
 443                 printk(KERN_ERR "vga_switcheroo: delayed switching failed %d\n", ret);
 444
 445         vgasr_priv.delayed_switch_active = false;
 446         err = 0;
 447 err:
 448         mutex_unlock(&vgasr_mutex);
 449         return err;
 450 }
 451 EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);
 452