drivers/gpu/drm/drm_fops.c

   1 /**
   2  * \file drm_fops.c
   3  * File operations for DRM
   4  *
   5  * \author Rickard E. (Rik) Faith <faith@valinux.com>
   6  * \author Daryll Strauss <daryll@valinux.com>
   7  * \author Gareth Hughes <gareth@valinux.com>
   8  */
   9
  10 /*
  11  * Created: Mon Jan  4 08:58:31 1999 by faith@valinux.com
  12  *
  13  * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
  14  * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
  15  * All Rights Reserved.
  16  *
  17  * Permission is hereby granted, free of charge, to any person obtaining a
  18  * copy of this software and associated documentation files (the "Software"),
  19  * to deal in the Software without restriction, including without limitation
  20  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  21  * and/or sell copies of the Software, and to permit persons to whom the
  22  * Software is furnished to do so, subject to the following conditions:
  23  *
  24  * The above copyright notice and this permission notice (including the next
  25  * paragraph) shall be included in all copies or substantial portions of the
  26  * Software.
  27  *
  28  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  29  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  30  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  31  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  32  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  33  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  34  * OTHER DEALINGS IN THE SOFTWARE.
  35  */
  36
  37 #include "drmP.h"
  38 #include <linux/poll.h>
  39 #include <linux/slab.h>
  40 #include <linux/module.h>
  41
  42 /* from BKL pushdown: note that nothing else serializes idr_find() */
  43 DEFINE_MUTEX(drm_global_mutex);
  44 EXPORT_SYMBOL(drm_global_mutex);
  45
  46 static int drm_open_helper(struct inode *inode, struct file *filp,
  47                            struct drm_device * dev);
  48
  49 static int drm_setup(struct drm_device * dev)
  50 {
  51         int i;
  52         int ret;
  53
  54         if (dev->driver->firstopen) {
  55                 ret = dev->driver->firstopen(dev);
  56                 if (ret != 0)
  57                         return ret;
  58         }
  59
  60         atomic_set(&dev->ioctl_count, 0);
  61         atomic_set(&dev->vma_count, 0);
  62
  63         if (drm_core_check_feature(dev, DRIVER_HAVE_DMA) &&
  64             !drm_core_check_feature(dev, DRIVER_MODESET)) {
  65                 dev->buf_use = 0;
  66                 atomic_set(&dev->buf_alloc, 0);
  67
  68                 i = drm_dma_setup(dev);
  69                 if (i < 0)
  70                         return i;
  71         }
  72
  73         for (i = 0; i < ARRAY_SIZE(dev->counts); i++)
  74                 atomic_set(&dev->counts[i], 0);
  75
  76         dev->sigdata.lock = NULL;
  77
  78         dev->queue_count = 0;
  79         dev->queue_reserved = 0;
  80         dev->queue_slots = 0;
  81         dev->queuelist = NULL;
  82         dev->context_flag = 0;
  83         dev->interrupt_flag = 0;
  84         dev->dma_flag = 0;
  85         dev->last_context = 0;
  86         dev->last_switch = 0;
  87         dev->last_checked = 0;
  88         init_waitqueue_head(&dev->context_wait);
  89         dev->if_version = 0;
  90
  91         dev->ctx_start = 0;
  92         dev->lck_start = 0;
  93
  94         dev->buf_async = NULL;
  95         init_waitqueue_head(&dev->buf_readers);
  96         init_waitqueue_head(&dev->buf_writers);
  97
  98         DRM_DEBUG("\n");
  99
 100         /*
 101          * The kernel's context could be created here, but is now created
 102          * in drm_dma_enqueue.  This is more resource-efficient for
 103          * hardware that does not do DMA, but may mean that
 104          * drm_select_queue fails between the time the interrupt is
 105          * initialized and the time the queues are initialized.
 106          */
 107
 108         return 0;
 109 }
 110
 111 /**
 112  * Open file.
 113  *
 114  * \param inode device inode
 115  * \param filp file pointer.
 116  * \return zero on success or a negative number on failure.
 117  *
 118  * Searches the DRM device with the same minor number, calls open_helper(), and
 119  * increments the device open count. If the open count was previous at zero,
 120  * i.e., it's the first that the device is open, then calls setup().
 121  */
 122 int drm_open(struct inode *inode, struct file *filp)
 123 {
 124         struct drm_device *dev = NULL;
 125         int minor_id = iminor(inode);
 126         struct drm_minor *minor;
 127         int retcode = 0;
 128
 129         minor = idr_find(&drm_minors_idr, minor_id);
 130         if (!minor)
 131                 return -ENODEV;
 132
 133         if (!(dev = minor->dev))
 134                 return -ENODEV;
 135
 136         if (drm_device_is_unplugged(dev))
 137                 return -ENODEV;
 138
 139         retcode = drm_open_helper(inode, filp, dev);
 140         if (!retcode) {
 141                 atomic_inc(&dev->counts[_DRM_STAT_OPENS]);
 142                 if (!dev->open_count++)
 143                         retcode = drm_setup(dev);
 144         }
 145         if (!retcode) {
 146                 mutex_lock(&dev->struct_mutex);
 147                 if (minor->type == DRM_MINOR_LEGACY) {
 148                         if (dev->dev_mapping == NULL)
 149                                 dev->dev_mapping = inode->i_mapping;
 150                         else if (dev->dev_mapping != inode->i_mapping)
 151                                 retcode = -ENODEV;
 152                 }
 153                 mutex_unlock(&dev->struct_mutex);
 154         }
 155
 156         return retcode;
 157 }
 158 EXPORT_SYMBOL(drm_open);
 159
 160 /**
 161  * File \c open operation.
 162  *
 163  * \param inode device inode.
 164  * \param filp file pointer.
 165  *
 166  * Puts the dev->fops corresponding to the device minor number into
 167  * \p filp, call the \c open method, and restore the file operations.
 168  */
 169 int drm_stub_open(struct inode *inode, struct file *filp)
 170 {
 171         struct drm_device *dev = NULL;
 172         struct drm_minor *minor;
 173         int minor_id = iminor(inode);
 174         int err = -ENODEV;
 175         const struct file_operations *old_fops;
 176
 177         DRM_DEBUG("\n");
 178
 179         mutex_lock(&drm_global_mutex);
 180         minor = idr_find(&drm_minors_idr, minor_id);
 181         if (!minor)
 182                 goto out;
 183
 184         if (!(dev = minor->dev))
 185                 goto out;
 186
 187         if (drm_device_is_unplugged(dev))
 188                 goto out;
 189
 190         old_fops = filp->f_op;
 191         filp->f_op = fops_get(dev->driver->fops);
 192         if (filp->f_op == NULL) {
 193                 filp->f_op = old_fops;
 194                 goto out;
 195         }
 196         if (filp->f_op->open && (err = filp->f_op->open(inode, filp))) {
 197                 fops_put(filp->f_op);
 198                 filp->f_op = fops_get(old_fops);
 199         }
 200         fops_put(old_fops);
 201
 202 out:
 203         mutex_unlock(&drm_global_mutex);
 204         return err;
 205 }
 206
 207 /**
 208  * Check whether DRI will run on this CPU.
 209  *
 210  * \return non-zero if the DRI will run on this CPU, or zero otherwise.
 211  */
 212 static int drm_cpu_valid(void)
 213 {
 214 #if defined(__i386__)
 215         if (boot_cpu_data.x86 == 3)
 216                 return 0;       /* No cmpxchg on a 386 */
 217 #endif
 218 #if defined(__sparc__) && !defined(__sparc_v9__)
 219         return 0;               /* No cmpxchg before v9 sparc. */
 220 #endif
 221         return 1;
 222 }
 223
 224 /**
 225  * Called whenever a process opens /dev/drm.
 226  *
 227  * \param inode device inode.
 228  * \param filp file pointer.
 229  * \param dev device.
 230  * \return zero on success or a negative number on failure.
 231  *
 232  * Creates and initializes a drm_file structure for the file private data in \p
 233  * filp and add it into the double linked list in \p dev.
 234  */
 235 static int drm_open_helper(struct inode *inode, struct file *filp,
 236                            struct drm_device * dev)
 237 {
 238         int minor_id = iminor(inode);
 239         struct drm_file *priv;
 240         int ret;
 241
 242         if (filp->f_flags & O_EXCL)
 243                 return -EBUSY;  /* No exclusive opens */
 244         if (!drm_cpu_valid())
 245                 return -EINVAL;
 246         if (dev->switch_power_state != DRM_SWITCH_POWER_ON)
 247                 return -EINVAL;
 248
 249         DRM_DEBUG("pid = %d, minor = %d\n", task_pid_nr(current), minor_id);
 250
 251         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 252         if (!priv)
 253                 return -ENOMEM;
 254
 255         filp->private_data = priv;
 256         priv->filp = filp;
 257         priv->uid = current_euid();
 258         priv->pid = task_pid_nr(current);
 259         priv->minor = idr_find(&drm_minors_idr, minor_id);
 260         priv->ioctl_count = 0;
 261         /* for compatibility root is always authenticated */
 262         priv->authenticated = capable(CAP_SYS_ADMIN);
 263         priv->lock_count = 0;
 264
 265         INIT_LIST_HEAD(&priv->lhead);
 266         INIT_LIST_HEAD(&priv->fbs);
 267         INIT_LIST_HEAD(&priv->event_list);
 268         init_waitqueue_head(&priv->event_wait);
 269         priv->event_space = 4096; /* set aside 4k for event buffer */
 270
 271         if (dev->driver->driver_features & DRIVER_GEM)
 272                 drm_gem_open(dev, priv);
 273
 274         if (dev->driver->open) {
 275                 ret = dev->driver->open(dev, priv);
 276                 if (ret < 0)
 277                         goto out_free;
 278         }
 279
 280
 281         /* if there is no current master make this fd it */
 282         mutex_lock(&dev->struct_mutex);
 283         if (!priv->minor->master) {
 284                 /* create a new master */
 285                 priv->minor->master = drm_master_create(priv->minor);
 286                 if (!priv->minor->master) {
 287                         mutex_unlock(&dev->struct_mutex);
 288                         ret = -ENOMEM;
 289                         goto out_free;
 290                 }
 291
 292                 priv->is_master = 1;
 293                 /* take another reference for the copy in the local file priv */
 294                 priv->master = drm_master_get(priv->minor->master);
 295
 296                 priv->authenticated = 1;
 297
 298                 mutex_unlock(&dev->struct_mutex);
 299                 if (dev->driver->master_create) {
 300                         ret = dev->driver->master_create(dev, priv->master);
 301                         if (ret) {
 302                                 mutex_lock(&dev->struct_mutex);
 303                                 /* drop both references if this fails */
 304                                 drm_master_put(&priv->minor->master);
 305                                 drm_master_put(&priv->master);
 306                                 mutex_unlock(&dev->struct_mutex);
 307                                 goto out_free;
 308                         }
 309                 }
 310                 mutex_lock(&dev->struct_mutex);
 311                 if (dev->driver->master_set) {
 312                         ret = dev->driver->master_set(dev, priv, true);
 313                         if (ret) {
 314                                 /* drop both references if this fails */
 315                                 drm_master_put(&priv->minor->master);
 316                                 drm_master_put(&priv->master);
 317                                 mutex_unlock(&dev->struct_mutex);
 318                                 goto out_free;
 319                         }
 320                 }
 321                 mutex_unlock(&dev->struct_mutex);
 322         } else {
 323                 /* get a reference to the master */
 324                 priv->master = drm_master_get(priv->minor->master);
 325                 mutex_unlock(&dev->struct_mutex);
 326         }
 327
 328         mutex_lock(&dev->struct_mutex);
 329         list_add(&priv->lhead, &dev->filelist);
 330         mutex_unlock(&dev->struct_mutex);
 331
 332 #ifdef __alpha__
 333         /*
 334          * Default the hose
 335          */
 336         if (!dev->hose) {
 337                 struct pci_dev *pci_dev;
 338                 pci_dev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, NULL);
 339                 if (pci_dev) {
 340                         dev->hose = pci_dev->sysdata;
 341                         pci_dev_put(pci_dev);
 342                 }
 343                 if (!dev->hose) {
 344                         struct pci_bus *b = pci_bus_b(pci_root_buses.next);
 345                         if (b)
 346                                 dev->hose = b->sysdata;
 347                 }
 348         }
 349 #endif
 350
 351         return 0;
 352       out_free:
 353         kfree(priv);
 354         filp->private_data = NULL;
 355         return ret;
 356 }
 357
 358 /** No-op. */
 359 int drm_fasync(int fd, struct file *filp, int on)
 360 {
 361         struct drm_file *priv = filp->private_data;
 362         struct drm_device *dev = priv->minor->dev;
 363
 364         DRM_DEBUG("fd = %d, device = 0x%lx\n", fd,
 365                   (long)old_encode_dev(priv->minor->device));
 366         return fasync_helper(fd, filp, on, &dev->buf_async);
 367 }
 368 EXPORT_SYMBOL(drm_fasync);
 369
 370 /*
 371  * Reclaim locked buffers; note that this may be a bad idea if the current
 372  * context doesn't have the hw lock...
 373  */
 374 static void drm_reclaim_locked_buffers(struct drm_device *dev, struct file *f)
 375 {
 376         struct drm_file *file_priv = f->private_data;
 377
 378         if (drm_i_have_hw_lock(dev, file_priv)) {
 379                 dev->driver->reclaim_buffers_locked(dev, file_priv);
 380         } else {
 381                 unsigned long _end = jiffies + 3 * DRM_HZ;
 382                 int locked = 0;
 383
 384                 drm_idlelock_take(&file_priv->master->lock);
 385
 386                 /*
 387                  * Wait for a while.
 388                  */
 389                 do {
 390                         spin_lock_bh(&file_priv->master->lock.spinlock);
 391                         locked = file_priv->master->lock.idle_has_lock;
 392                         spin_unlock_bh(&file_priv->master->lock.spinlock);
 393                         if (locked)
 394                                 break;
 395                         schedule();
 396                 } while (!time_after_eq(jiffies, _end));
 397
 398                 if (!locked) {
 399                         DRM_ERROR("reclaim_buffers_locked() deadlock. Please rework this\n"
 400                                   "\tdriver to use reclaim_buffers_idlelocked() instead.\n"
 401                                   "\tI will go on reclaiming the buffers anyway.\n");
 402                 }
 403
 404                 dev->driver->reclaim_buffers_locked(dev, file_priv);
 405                 drm_idlelock_release(&file_priv->master->lock);
 406         }
 407 }
 408
 409 static void drm_master_release(struct drm_device *dev, struct file *filp)
 410 {
 411         struct drm_file *file_priv = filp->private_data;
 412
 413         if (dev->driver->reclaim_buffers_locked &&
 414             file_priv->master->lock.hw_lock)
 415                 drm_reclaim_locked_buffers(dev, filp);
 416
 417         if (dev->driver->reclaim_buffers_idlelocked &&
 418             file_priv->master->lock.hw_lock) {
 419                 drm_idlelock_take(&file_priv->master->lock);
 420                 dev->driver->reclaim_buffers_idlelocked(dev, file_priv);
 421                 drm_idlelock_release(&file_priv->master->lock);
 422         }
 423
 424
 425         if (drm_i_have_hw_lock(dev, file_priv)) {
 426                 DRM_DEBUG("File %p released, freeing lock for context %d\n",
 427                           filp, _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock));
 428                 drm_lock_free(&file_priv->master->lock,
 429                               _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock));
 430         }
 431
 432         if (drm_core_check_feature(dev, DRIVER_HAVE_DMA) &&
 433             !dev->driver->reclaim_buffers_locked) {
 434                 dev->driver->reclaim_buffers(dev, file_priv);
 435         }
 436 }
 437
 438 static void drm_events_release(struct drm_file *file_priv)
 439 {
 440         struct drm_device *dev = file_priv->minor->dev;
 441         struct drm_pending_event *e, *et;
 442         struct drm_pending_vblank_event *v, *vt;
 443         unsigned long flags;
 444
 445         spin_lock_irqsave(&dev->event_lock, flags);
 446
 447         /* Remove pending flips */
 448         list_for_each_entry_safe(v, vt, &dev->vblank_event_list, base.link)
 449                 if (v->base.file_priv == file_priv) {
 450                         list_del(&v->base.link);
 451                         drm_vblank_put(dev, v->pipe);
 452                         v->base.destroy(&v->base);
 453                 }
 454
 455         /* Remove unconsumed events */
 456         list_for_each_entry_safe(e, et, &file_priv->event_list, link)
 457                 e->destroy(e);
 458
 459         spin_unlock_irqrestore(&dev->event_lock, flags);
 460 }
 461
 462 /**
 463  * Release file.
 464  *
 465  * \param inode device inode
 466  * \param file_priv DRM file private.
 467  * \return zero on success or a negative number on failure.
 468  *
 469  * If the hardware lock is held then free it, and take it again for the kernel
 470  * context since it's necessary to reclaim buffers. Unlink the file private
 471  * data from its list and free it. Decreases the open count and if it reaches
 472  * zero calls drm_lastclose().
 473  */
 474 int drm_release(struct inode *inode, struct file *filp)
 475 {
 476         struct drm_file *file_priv = filp->private_data;
 477         struct drm_device *dev = file_priv->minor->dev;
 478         int retcode = 0;
 479
 480         mutex_lock(&drm_global_mutex);
 481
 482         DRM_DEBUG("open_count = %d\n", dev->open_count);
 483
 484         if (dev->driver->preclose)
 485                 dev->driver->preclose(dev, file_priv);
 486
 487         /* ========================================================
 488          * Begin inline drm_release
 489          */
 490
 491         DRM_DEBUG("pid = %d, device = 0x%lx, open_count = %d\n",
 492                   task_pid_nr(current),
 493                   (long)old_encode_dev(file_priv->minor->device),
 494                   dev->open_count);
 495
 496         /* Release any auth tokens that might point to this file_priv,
 497            (do that under the drm_global_mutex) */
 498         if (file_priv->magic)
 499                 (void) drm_remove_magic(file_priv->master, file_priv->magic);
 500
 501         /* if the master has gone away we can't do anything with the lock */
 502         if (file_priv->minor->master)
 503                 drm_master_release(dev, filp);
 504
 505         drm_events_release(file_priv);
 506
 507         if (dev->driver->driver_features & DRIVER_GEM)
 508                 drm_gem_release(dev, file_priv);
 509
 510         if (dev->driver->driver_features & DRIVER_MODESET)
 511                 drm_fb_release(file_priv);
 512
 513         mutex_lock(&dev->ctxlist_mutex);
 514         if (!list_empty(&dev->ctxlist)) {
 515                 struct drm_ctx_list *pos, *n;
 516
 517                 list_for_each_entry_safe(pos, n, &dev->ctxlist, head) {
 518                         if (pos->tag == file_priv &&
 519                             pos->handle != DRM_KERNEL_CONTEXT) {
 520                                 if (dev->driver->context_dtor)
 521                                         dev->driver->context_dtor(dev,
 522                                                                   pos->handle);
 523
 524                                 drm_ctxbitmap_free(dev, pos->handle);
 525
 526                                 list_del(&pos->head);
 527                                 kfree(pos);
 528                                 --dev->ctx_count;
 529                         }
 530                 }
 531         }
 532         mutex_unlock(&dev->ctxlist_mutex);
 533
 534         mutex_lock(&dev->struct_mutex);
 535
 536         if (file_priv->is_master) {
 537                 struct drm_master *master = file_priv->master;
 538                 struct drm_file *temp;
 539                 list_for_each_entry(temp, &dev->filelist, lhead) {
 540                         if ((temp->master == file_priv->master) &&
 541                             (temp != file_priv))
 542                                 temp->authenticated = 0;
 543                 }
 544
 545                 /**
 546                  * Since the master is disappearing, so is the
 547                  * possibility to lock.
 548                  */
 549
 550                 if (master->lock.hw_lock) {
 551                         if (dev->sigdata.lock == master->lock.hw_lock)
 552                                 dev->sigdata.lock = NULL;
 553                         master->lock.hw_lock = NULL;
 554                         master->lock.file_priv = NULL;
 555                         wake_up_interruptible_all(&master->lock.lock_queue);
 556                 }
 557
 558                 if (file_priv->minor->master == file_priv->master) {
 559                         /* drop the reference held my the minor */
 560                         if (dev->driver->master_drop)
 561                                 dev->driver->master_drop(dev, file_priv, true);
 562                         drm_master_put(&file_priv->minor->master);
 563                 }
 564         }
 565
 566         /* drop the reference held my the file priv */
 567         drm_master_put(&file_priv->master);
 568         file_priv->is_master = 0;
 569         list_del(&file_priv->lhead);
 570         mutex_unlock(&dev->struct_mutex);
 571
 572         if (dev->driver->postclose)
 573                 dev->driver->postclose(dev, file_priv);
 574         kfree(file_priv);
 575
 576         /* ========================================================
 577          * End inline drm_release
 578          */
 579
 580         atomic_inc(&dev->counts[_DRM_STAT_CLOSES]);
 581         if (!--dev->open_count) {
 582                 if (atomic_read(&dev->ioctl_count)) {
 583                         DRM_ERROR("Device busy: %d\n",
 584                                   atomic_read(&dev->ioctl_count));
 585                         retcode = -EBUSY;
 586                 } else
 587                         retcode = drm_lastclose(dev);
 588                 if (drm_device_is_unplugged(dev))
 589                         drm_put_dev(dev);
 590         }
 591         mutex_unlock(&drm_global_mutex);
 592
 593         return retcode;
 594 }
 595 EXPORT_SYMBOL(drm_release);
 596
 597 static bool
 598 drm_dequeue_event(struct drm_file *file_priv,
 599                   size_t total, size_t max, struct drm_pending_event **out)
 600 {
 601         struct drm_device *dev = file_priv->minor->dev;
 602         struct drm_pending_event *e;
 603         unsigned long flags;
 604         bool ret = false;
 605
 606         spin_lock_irqsave(&dev->event_lock, flags);
 607
 608         *out = NULL;
 609         if (list_empty(&file_priv->event_list))
 610                 goto out;
 611         e = list_first_entry(&file_priv->event_list,
 612                              struct drm_pending_event, link);
 613         if (e->event->length + total > max)
 614                 goto out;
 615
 616         file_priv->event_space += e->event->length;
 617         list_del(&e->link);
 618         *out = e;
 619         ret = true;
 620
 621 out:
 622         spin_unlock_irqrestore(&dev->event_lock, flags);
 623         return ret;
 624 }
 625
 626 ssize_t drm_read(struct file *filp, char __user *buffer,
 627                  size_t count, loff_t *offset)
 628 {
 629         struct drm_file *file_priv = filp->private_data;
 630         struct drm_pending_event *e;
 631         size_t total;
 632         ssize_t ret;
 633
 634         ret = wait_event_interruptible(file_priv->event_wait,
 635                                        !list_empty(&file_priv->event_list));
 636         if (ret < 0)
 637                 return ret;
 638
 639         total = 0;
 640         while (drm_dequeue_event(file_priv, total, count, &e)) {
 641                 if (copy_to_user(buffer + total,
 642                                  e->event, e->event->length)) {
 643                         total = -EFAULT;
 644                         break;
 645                 }
 646
 647                 total += e->event->length;
 648                 e->destroy(e);
 649         }
 650
 651         return total;
 652 }
 653 EXPORT_SYMBOL(drm_read);
 654
 655 unsigned int drm_poll(struct file *filp, struct poll_table_struct *wait)
 656 {
 657         struct drm_file *file_priv = filp->private_data;
 658         unsigned int mask = 0;
 659
 660         poll_wait(filp, &file_priv->event_wait, wait);
 661
 662         if (!list_empty(&file_priv->event_list))
 663                 mask |= POLLIN | POLLRDNORM;
 664
 665         return mask;
 666 }
 667 EXPORT_SYMBOL(drm_poll);