linux/drivers/gpu/vga/vga_switcheroo.c
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   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
  31struct 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
  42static DEFINE_MUTEX(vgasr_mutex);
  43
  44struct 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
  59static int vga_switcheroo_debugfs_init(struct vgasr_priv *priv);
  60static void vga_switcheroo_debugfs_fini(struct vgasr_priv *priv);
  61
  62/* only one switcheroo per system */
  63static struct vgasr_priv vgasr_priv;
  64
  65int 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}
  77EXPORT_SYMBOL(vga_switcheroo_register_handler);
  78
  79void vga_switcheroo_unregister_handler(void)
  80{
  81        mutex_lock(&vgasr_mutex);
  82        vgasr_priv.handler = NULL;
  83        mutex_unlock(&vgasr_mutex);
  84}
  85EXPORT_SYMBOL(vga_switcheroo_unregister_handler);
  86
  87static 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
 105int 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}
 138EXPORT_SYMBOL(vga_switcheroo_register_client);
 139
 140void 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}
 157EXPORT_SYMBOL(vga_switcheroo_unregister_client);
 158
 159void 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}
 173EXPORT_SYMBOL(vga_switcheroo_client_fb_set);
 174
 175static 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
 190static int vga_switcheroo_debugfs_open(struct inode *inode, struct file *file)
 191{
 192        return single_open(file, vga_switcheroo_show, NULL);
 193}
 194
 195static 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
 205static 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 */
 216static 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 */
 240static 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
 277static ssize_t
 278vga_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
 402out:
 403        mutex_unlock(&vgasr_mutex);
 404        return cnt;
 405}
 406
 407static 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
 416static 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
 428static 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;
 447fail:
 448        vga_switcheroo_debugfs_fini(priv);
 449        return -1;
 450}
 451
 452int 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;
 487err:
 488        mutex_unlock(&vgasr_mutex);
 489        return err;
 490}
 491EXPORT_SYMBOL(vga_switcheroo_process_delayed_switch);
 492
 493