]> www.pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - drivers/gpu/drm/drm_irq.c
Merge branch 'v28-range-hrtimers-for-linus-v2' of git://git.kernel.org/pub/scm/linux...
[linux-2.6-omap-h63xx.git] / drivers / gpu / drm / drm_irq.c
index 53f0e5af1cc82fd2379b8a48db2afe0ea8d60298..212a94f715b23cf2db6103a301c91f9c6545a4ce 100644 (file)
@@ -63,7 +63,7 @@ int drm_irq_by_busid(struct drm_device *dev, void *data,
            p->devnum != PCI_SLOT(dev->pdev->devfn) || p->funcnum != PCI_FUNC(dev->pdev->devfn))
                return -EINVAL;
 
-       p->irq = dev->irq;
+       p->irq = dev->pdev->irq;
 
        DRM_DEBUG("%d:%d:%d => IRQ %d\n", p->busnum, p->devnum, p->funcnum,
                  p->irq);
@@ -71,25 +71,137 @@ int drm_irq_by_busid(struct drm_device *dev, void *data,
        return 0;
 }
 
+static void vblank_disable_fn(unsigned long arg)
+{
+       struct drm_device *dev = (struct drm_device *)arg;
+       unsigned long irqflags;
+       int i;
+
+       if (!dev->vblank_disable_allowed)
+               return;
+
+       for (i = 0; i < dev->num_crtcs; i++) {
+               spin_lock_irqsave(&dev->vbl_lock, irqflags);
+               if (atomic_read(&dev->vblank_refcount[i]) == 0 &&
+                   dev->vblank_enabled[i]) {
+                       DRM_DEBUG("disabling vblank on crtc %d\n", i);
+                       dev->last_vblank[i] =
+                               dev->driver->get_vblank_counter(dev, i);
+                       dev->driver->disable_vblank(dev, i);
+                       dev->vblank_enabled[i] = 0;
+               }
+               spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+       }
+}
+
+static void drm_vblank_cleanup(struct drm_device *dev)
+{
+       /* Bail if the driver didn't call drm_vblank_init() */
+       if (dev->num_crtcs == 0)
+               return;
+
+       del_timer(&dev->vblank_disable_timer);
+
+       vblank_disable_fn((unsigned long)dev);
+
+       drm_free(dev->vbl_queue, sizeof(*dev->vbl_queue) * dev->num_crtcs,
+                DRM_MEM_DRIVER);
+       drm_free(dev->vbl_sigs, sizeof(*dev->vbl_sigs) * dev->num_crtcs,
+                DRM_MEM_DRIVER);
+       drm_free(dev->_vblank_count, sizeof(*dev->_vblank_count) *
+                dev->num_crtcs, DRM_MEM_DRIVER);
+       drm_free(dev->vblank_refcount, sizeof(*dev->vblank_refcount) *
+                dev->num_crtcs, DRM_MEM_DRIVER);
+       drm_free(dev->vblank_enabled, sizeof(*dev->vblank_enabled) *
+                dev->num_crtcs, DRM_MEM_DRIVER);
+       drm_free(dev->last_vblank, sizeof(*dev->last_vblank) * dev->num_crtcs,
+                DRM_MEM_DRIVER);
+       drm_free(dev->vblank_inmodeset, sizeof(*dev->vblank_inmodeset) *
+                dev->num_crtcs, DRM_MEM_DRIVER);
+
+       dev->num_crtcs = 0;
+}
+
+int drm_vblank_init(struct drm_device *dev, int num_crtcs)
+{
+       int i, ret = -ENOMEM;
+
+       setup_timer(&dev->vblank_disable_timer, vblank_disable_fn,
+                   (unsigned long)dev);
+       spin_lock_init(&dev->vbl_lock);
+       atomic_set(&dev->vbl_signal_pending, 0);
+       dev->num_crtcs = num_crtcs;
+
+       dev->vbl_queue = drm_alloc(sizeof(wait_queue_head_t) * num_crtcs,
+                                  DRM_MEM_DRIVER);
+       if (!dev->vbl_queue)
+               goto err;
+
+       dev->vbl_sigs = drm_alloc(sizeof(struct list_head) * num_crtcs,
+                                 DRM_MEM_DRIVER);
+       if (!dev->vbl_sigs)
+               goto err;
+
+       dev->_vblank_count = drm_alloc(sizeof(atomic_t) * num_crtcs,
+                                     DRM_MEM_DRIVER);
+       if (!dev->_vblank_count)
+               goto err;
+
+       dev->vblank_refcount = drm_alloc(sizeof(atomic_t) * num_crtcs,
+                                        DRM_MEM_DRIVER);
+       if (!dev->vblank_refcount)
+               goto err;
+
+       dev->vblank_enabled = drm_calloc(num_crtcs, sizeof(int),
+                                        DRM_MEM_DRIVER);
+       if (!dev->vblank_enabled)
+               goto err;
+
+       dev->last_vblank = drm_calloc(num_crtcs, sizeof(u32), DRM_MEM_DRIVER);
+       if (!dev->last_vblank)
+               goto err;
+
+       dev->vblank_inmodeset = drm_calloc(num_crtcs, sizeof(int),
+                                        DRM_MEM_DRIVER);
+       if (!dev->vblank_inmodeset)
+               goto err;
+
+       /* Zero per-crtc vblank stuff */
+       for (i = 0; i < num_crtcs; i++) {
+               init_waitqueue_head(&dev->vbl_queue[i]);
+               INIT_LIST_HEAD(&dev->vbl_sigs[i]);
+               atomic_set(&dev->_vblank_count[i], 0);
+               atomic_set(&dev->vblank_refcount[i], 0);
+       }
+
+       dev->vblank_disable_allowed = 0;
+
+       return 0;
+
+err:
+       drm_vblank_cleanup(dev);
+       return ret;
+}
+EXPORT_SYMBOL(drm_vblank_init);
+
 /**
  * Install IRQ handler.
  *
  * \param dev DRM device.
- * \param irq IRQ number.
  *
- * Initializes the IRQ related data, and setups drm_device::vbl_queue. Installs the handler, calling the driver
+ * Initializes the IRQ related data. Installs the handler, calling the driver
  * \c drm_driver_irq_preinstall() and \c drm_driver_irq_postinstall() functions
  * before and after the installation.
  */
-static int drm_irq_install(struct drm_device * dev)
+int drm_irq_install(struct drm_device *dev)
 {
-       int ret;
+       int ret = 0;
        unsigned long sh_flags = 0;
 
        if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
                return -EINVAL;
 
-       if (dev->irq == 0)
+       if (dev->pdev->irq == 0)
                return -EINVAL;
 
        mutex_lock(&dev->struct_mutex);
@@ -107,18 +219,7 @@ static int drm_irq_install(struct drm_device * dev)
        dev->irq_enabled = 1;
        mutex_unlock(&dev->struct_mutex);
 
-       DRM_DEBUG("irq=%d\n", dev->irq);
-
-       if (drm_core_check_feature(dev, DRIVER_IRQ_VBL)) {
-               init_waitqueue_head(&dev->vbl_queue);
-
-               spin_lock_init(&dev->vbl_lock);
-
-               INIT_LIST_HEAD(&dev->vbl_sigs);
-               INIT_LIST_HEAD(&dev->vbl_sigs2);
-
-               dev->vbl_pending = 0;
-       }
+       DRM_DEBUG("irq=%d\n", dev->pdev->irq);
 
        /* Before installing handler */
        dev->driver->irq_preinstall(dev);
@@ -127,8 +228,9 @@ static int drm_irq_install(struct drm_device * dev)
        if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
                sh_flags = IRQF_SHARED;
 
-       ret = request_irq(dev->irq, dev->driver->irq_handler,
+       ret = request_irq(drm_dev_to_irq(dev), dev->driver->irq_handler,
                          sh_flags, dev->devname, dev);
+
        if (ret < 0) {
                mutex_lock(&dev->struct_mutex);
                dev->irq_enabled = 0;
@@ -137,10 +239,16 @@ static int drm_irq_install(struct drm_device * dev)
        }
 
        /* After installing handler */
-       dev->driver->irq_postinstall(dev);
+       ret = dev->driver->irq_postinstall(dev);
+       if (ret < 0) {
+               mutex_lock(&dev->struct_mutex);
+               dev->irq_enabled = 0;
+               mutex_unlock(&dev->struct_mutex);
+       }
 
-       return 0;
+       return ret;
 }
+EXPORT_SYMBOL(drm_irq_install);
 
 /**
  * Uninstall the IRQ handler.
@@ -164,17 +272,18 @@ int drm_irq_uninstall(struct drm_device * dev)
        if (!irq_enabled)
                return -EINVAL;
 
-       DRM_DEBUG("irq=%d\n", dev->irq);
+       DRM_DEBUG("irq=%d\n", dev->pdev->irq);
 
        dev->driver->irq_uninstall(dev);
 
-       free_irq(dev->irq, dev);
+       free_irq(dev->pdev->irq, dev);
+
+       drm_vblank_cleanup(dev);
 
        dev->locked_tasklet_func = NULL;
 
        return 0;
 }
-
 EXPORT_SYMBOL(drm_irq_uninstall);
 
 /**
@@ -201,7 +310,7 @@ int drm_control(struct drm_device *dev, void *data,
                if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
                        return 0;
                if (dev->if_version < DRM_IF_VERSION(1, 2) &&
-                   ctl->irq != dev->irq)
+                   ctl->irq != dev->pdev->irq)
                        return -EINVAL;
                return drm_irq_install(dev);
        case DRM_UNINST_HANDLER:
@@ -213,6 +322,174 @@ int drm_control(struct drm_device *dev, void *data,
        }
 }
 
+/**
+ * drm_vblank_count - retrieve "cooked" vblank counter value
+ * @dev: DRM device
+ * @crtc: which counter to retrieve
+ *
+ * Fetches the "cooked" vblank count value that represents the number of
+ * vblank events since the system was booted, including lost events due to
+ * modesetting activity.
+ */
+u32 drm_vblank_count(struct drm_device *dev, int crtc)
+{
+       return atomic_read(&dev->_vblank_count[crtc]);
+}
+EXPORT_SYMBOL(drm_vblank_count);
+
+/**
+ * drm_update_vblank_count - update the master vblank counter
+ * @dev: DRM device
+ * @crtc: counter to update
+ *
+ * Call back into the driver to update the appropriate vblank counter
+ * (specified by @crtc).  Deal with wraparound, if it occurred, and
+ * update the last read value so we can deal with wraparound on the next
+ * call if necessary.
+ *
+ * Only necessary when going from off->on, to account for frames we
+ * didn't get an interrupt for.
+ *
+ * Note: caller must hold dev->vbl_lock since this reads & writes
+ * device vblank fields.
+ */
+static void drm_update_vblank_count(struct drm_device *dev, int crtc)
+{
+       u32 cur_vblank, diff;
+
+       /*
+        * Interrupts were disabled prior to this call, so deal with counter
+        * wrap if needed.
+        * NOTE!  It's possible we lost a full dev->max_vblank_count events
+        * here if the register is small or we had vblank interrupts off for
+        * a long time.
+        */
+       cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
+       diff = cur_vblank - dev->last_vblank[crtc];
+       if (cur_vblank < dev->last_vblank[crtc]) {
+               diff += dev->max_vblank_count;
+
+               DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
+                         crtc, dev->last_vblank[crtc], cur_vblank, diff);
+       }
+
+       DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n",
+                 crtc, diff);
+
+       atomic_add(diff, &dev->_vblank_count[crtc]);
+}
+
+/**
+ * drm_vblank_get - get a reference count on vblank events
+ * @dev: DRM device
+ * @crtc: which CRTC to own
+ *
+ * Acquire a reference count on vblank events to avoid having them disabled
+ * while in use.
+ *
+ * RETURNS
+ * Zero on success, nonzero on failure.
+ */
+int drm_vblank_get(struct drm_device *dev, int crtc)
+{
+       unsigned long irqflags;
+       int ret = 0;
+
+       spin_lock_irqsave(&dev->vbl_lock, irqflags);
+       /* Going from 0->1 means we have to enable interrupts again */
+       if (atomic_add_return(1, &dev->vblank_refcount[crtc]) == 1 &&
+           !dev->vblank_enabled[crtc]) {
+               ret = dev->driver->enable_vblank(dev, crtc);
+               DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", crtc, ret);
+               if (ret)
+                       atomic_dec(&dev->vblank_refcount[crtc]);
+               else {
+                       dev->vblank_enabled[crtc] = 1;
+                       drm_update_vblank_count(dev, crtc);
+               }
+       }
+       spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+
+       return ret;
+}
+EXPORT_SYMBOL(drm_vblank_get);
+
+/**
+ * drm_vblank_put - give up ownership of vblank events
+ * @dev: DRM device
+ * @crtc: which counter to give up
+ *
+ * Release ownership of a given vblank counter, turning off interrupts
+ * if possible.
+ */
+void drm_vblank_put(struct drm_device *dev, int crtc)
+{
+       /* Last user schedules interrupt disable */
+       if (atomic_dec_and_test(&dev->vblank_refcount[crtc]))
+               mod_timer(&dev->vblank_disable_timer, jiffies + 5*DRM_HZ);
+}
+EXPORT_SYMBOL(drm_vblank_put);
+
+/**
+ * drm_modeset_ctl - handle vblank event counter changes across mode switch
+ * @DRM_IOCTL_ARGS: standard ioctl arguments
+ *
+ * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
+ * ioctls around modesetting so that any lost vblank events are accounted for.
+ *
+ * Generally the counter will reset across mode sets.  If interrupts are
+ * enabled around this call, we don't have to do anything since the counter
+ * will have already been incremented.
+ */
+int drm_modeset_ctl(struct drm_device *dev, void *data,
+                   struct drm_file *file_priv)
+{
+       struct drm_modeset_ctl *modeset = data;
+       unsigned long irqflags;
+       int crtc, ret = 0;
+
+       /* If drm_vblank_init() hasn't been called yet, just no-op */
+       if (!dev->num_crtcs)
+               goto out;
+
+       crtc = modeset->crtc;
+       if (crtc >= dev->num_crtcs) {
+               ret = -EINVAL;
+               goto out;
+       }
+
+       /*
+        * To avoid all the problems that might happen if interrupts
+        * were enabled/disabled around or between these calls, we just
+        * have the kernel take a reference on the CRTC (just once though
+        * to avoid corrupting the count if multiple, mismatch calls occur),
+        * so that interrupts remain enabled in the interim.
+        */
+       switch (modeset->cmd) {
+       case _DRM_PRE_MODESET:
+               if (!dev->vblank_inmodeset[crtc]) {
+                       dev->vblank_inmodeset[crtc] = 1;
+                       drm_vblank_get(dev, crtc);
+               }
+               break;
+       case _DRM_POST_MODESET:
+               if (dev->vblank_inmodeset[crtc]) {
+                       spin_lock_irqsave(&dev->vbl_lock, irqflags);
+                       dev->vblank_disable_allowed = 1;
+                       dev->vblank_inmodeset[crtc] = 0;
+                       spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+                       drm_vblank_put(dev, crtc);
+               }
+               break;
+       default:
+               ret = -EINVAL;
+               break;
+       }
+
+out:
+       return ret;
+}
+
 /**
  * Wait for VBLANK.
  *
@@ -232,14 +509,14 @@ int drm_control(struct drm_device *dev, void *data,
  *
  * If a signal is not requested, then calls vblank_wait().
  */
-int drm_wait_vblank(struct drm_device *dev, void *data, struct drm_file *file_priv)
+int drm_wait_vblank(struct drm_device *dev, void *data,
+                   struct drm_file *file_priv)
 {
        union drm_wait_vblank *vblwait = data;
-       struct timeval now;
        int ret = 0;
-       unsigned int flags, seq;
+       unsigned int flags, seq, crtc;
 
-       if ((!dev->irq) || (!dev->irq_enabled))
+       if ((!dev->pdev->irq) || (!dev->irq_enabled))
                return -EINVAL;
 
        if (vblwait->request.type &
@@ -251,13 +528,17 @@ int drm_wait_vblank(struct drm_device *dev, void *data, struct drm_file *file_pr
        }
 
        flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
+       crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
 
-       if (!drm_core_check_feature(dev, (flags & _DRM_VBLANK_SECONDARY) ?
-                                   DRIVER_IRQ_VBL2 : DRIVER_IRQ_VBL))
+       if (crtc >= dev->num_crtcs)
                return -EINVAL;
 
-       seq = atomic_read((flags & _DRM_VBLANK_SECONDARY) ? &dev->vbl_received2
-                         : &dev->vbl_received);
+       ret = drm_vblank_get(dev, crtc);
+       if (ret) {
+               DRM_ERROR("failed to acquire vblank counter, %d\n", ret);
+               return ret;
+       }
+       seq = drm_vblank_count(dev, crtc);
 
        switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
        case _DRM_VBLANK_RELATIVE:
@@ -266,7 +547,8 @@ int drm_wait_vblank(struct drm_device *dev, void *data, struct drm_file *file_pr
        case _DRM_VBLANK_ABSOLUTE:
                break;
        default:
-               return -EINVAL;
+               ret = -EINVAL;
+               goto done;
        }
 
        if ((flags & _DRM_VBLANK_NEXTONMISS) &&
@@ -276,8 +558,7 @@ int drm_wait_vblank(struct drm_device *dev, void *data, struct drm_file *file_pr
 
        if (flags & _DRM_VBLANK_SIGNAL) {
                unsigned long irqflags;
-               struct list_head *vbl_sigs = (flags & _DRM_VBLANK_SECONDARY)
-                                     ? &dev->vbl_sigs2 : &dev->vbl_sigs;
+               struct list_head *vbl_sigs = &dev->vbl_sigs[crtc];
                struct drm_vbl_sig *vbl_sig;
 
                spin_lock_irqsave(&dev->vbl_lock, irqflags);
@@ -298,22 +579,32 @@ int drm_wait_vblank(struct drm_device *dev, void *data, struct drm_file *file_pr
                        }
                }
 
-               if (dev->vbl_pending >= 100) {
+               if (atomic_read(&dev->vbl_signal_pending) >= 100) {
                        spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
-                       return -EBUSY;
+                       ret = -EBUSY;
+                       goto done;
                }
 
-               dev->vbl_pending++;
-
                spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 
-               if (!
-                   (vbl_sig =
-                    drm_alloc(sizeof(struct drm_vbl_sig), DRM_MEM_DRIVER))) {
-                       return -ENOMEM;
+               vbl_sig = drm_calloc(1, sizeof(struct drm_vbl_sig),
+                                    DRM_MEM_DRIVER);
+               if (!vbl_sig) {
+                       ret = -ENOMEM;
+                       goto done;
+               }
+
+               /* Get a refcount on the vblank, which will be released by
+                * drm_vbl_send_signals().
+                */
+               ret = drm_vblank_get(dev, crtc);
+               if (ret) {
+                       drm_free(vbl_sig, sizeof(struct drm_vbl_sig),
+                                DRM_MEM_DRIVER);
+                       goto done;
                }
 
-               memset((void *)vbl_sig, 0, sizeof(*vbl_sig));
+               atomic_inc(&dev->vbl_signal_pending);
 
                vbl_sig->sequence = vblwait->request.sequence;
                vbl_sig->info.si_signo = vblwait->request.signal;
@@ -327,20 +618,29 @@ int drm_wait_vblank(struct drm_device *dev, void *data, struct drm_file *file_pr
 
                vblwait->reply.sequence = seq;
        } else {
-               if (flags & _DRM_VBLANK_SECONDARY) {
-                       if (dev->driver->vblank_wait2)
-                               ret = dev->driver->vblank_wait2(dev, &vblwait->request.sequence);
-               } else if (dev->driver->vblank_wait)
-                       ret =
-                           dev->driver->vblank_wait(dev,
-                                                    &vblwait->request.sequence);
-
-               do_gettimeofday(&now);
-               vblwait->reply.tval_sec = now.tv_sec;
-               vblwait->reply.tval_usec = now.tv_usec;
+               DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
+                         vblwait->request.sequence, crtc);
+               DRM_WAIT_ON(ret, dev->vbl_queue[crtc], 3 * DRM_HZ,
+                           ((drm_vblank_count(dev, crtc)
+                             - vblwait->request.sequence) <= (1 << 23)));
+
+               if (ret != -EINTR) {
+                       struct timeval now;
+
+                       do_gettimeofday(&now);
+
+                       vblwait->reply.tval_sec = now.tv_sec;
+                       vblwait->reply.tval_usec = now.tv_usec;
+                       vblwait->reply.sequence = drm_vblank_count(dev, crtc);
+                       DRM_DEBUG("returning %d to client\n",
+                                 vblwait->reply.sequence);
+               } else {
+                       DRM_DEBUG("vblank wait interrupted by signal\n");
+               }
        }
 
-      done:
+done:
+       drm_vblank_put(dev, crtc);
        return ret;
 }
 
@@ -348,44 +648,57 @@ int drm_wait_vblank(struct drm_device *dev, void *data, struct drm_file *file_pr
  * Send the VBLANK signals.
  *
  * \param dev DRM device.
+ * \param crtc CRTC where the vblank event occurred
  *
  * Sends a signal for each task in drm_device::vbl_sigs and empties the list.
  *
  * If a signal is not requested, then calls vblank_wait().
  */
-void drm_vbl_send_signals(struct drm_device * dev)
+static void drm_vbl_send_signals(struct drm_device *dev, int crtc)
 {
+       struct drm_vbl_sig *vbl_sig, *tmp;
+       struct list_head *vbl_sigs;
+       unsigned int vbl_seq;
        unsigned long flags;
-       int i;
 
        spin_lock_irqsave(&dev->vbl_lock, flags);
 
-       for (i = 0; i < 2; i++) {
-               struct drm_vbl_sig *vbl_sig, *tmp;
-               struct list_head *vbl_sigs = i ? &dev->vbl_sigs2 : &dev->vbl_sigs;
-               unsigned int vbl_seq = atomic_read(i ? &dev->vbl_received2 :
-                                                  &dev->vbl_received);
+       vbl_sigs = &dev->vbl_sigs[crtc];
+       vbl_seq = drm_vblank_count(dev, crtc);
 
-               list_for_each_entry_safe(vbl_sig, tmp, vbl_sigs, head) {
-                       if ((vbl_seq - vbl_sig->sequence) <= (1 << 23)) {
-                               vbl_sig->info.si_code = vbl_seq;
-                               send_sig_info(vbl_sig->info.si_signo,
-                                             &vbl_sig->info, vbl_sig->task);
+       list_for_each_entry_safe(vbl_sig, tmp, vbl_sigs, head) {
+           if ((vbl_seq - vbl_sig->sequence) <= (1 << 23)) {
+               vbl_sig->info.si_code = vbl_seq;
+               send_sig_info(vbl_sig->info.si_signo,
+                             &vbl_sig->info, vbl_sig->task);
 
-                               list_del(&vbl_sig->head);
-
-                               drm_free(vbl_sig, sizeof(*vbl_sig),
-                                        DRM_MEM_DRIVER);
+               list_del(&vbl_sig->head);
 
-                               dev->vbl_pending--;
-                       }
-               }
+               drm_free(vbl_sig, sizeof(*vbl_sig),
+                        DRM_MEM_DRIVER);
+               atomic_dec(&dev->vbl_signal_pending);
+               drm_vblank_put(dev, crtc);
+           }
        }
 
        spin_unlock_irqrestore(&dev->vbl_lock, flags);
 }
 
-EXPORT_SYMBOL(drm_vbl_send_signals);
+/**
+ * drm_handle_vblank - handle a vblank event
+ * @dev: DRM device
+ * @crtc: where this event occurred
+ *
+ * Drivers should call this routine in their vblank interrupt handlers to
+ * update the vblank counter and send any signals that may be pending.
+ */
+void drm_handle_vblank(struct drm_device *dev, int crtc)
+{
+       atomic_inc(&dev->_vblank_count[crtc]);
+       DRM_WAKEUP(&dev->vbl_queue[crtc]);
+       drm_vbl_send_signals(dev, crtc);
+}
+EXPORT_SYMBOL(drm_handle_vblank);
 
 /**
  * Tasklet wrapper function.