drm: Make the vblank disable timer per-crtc

Currently there's one per-device vblank disable timer, and it gets
reset wheneven the vblank refcount for any crtc drops to zero. That
means that one crtc could accidentally be keeping the vblank interrupts
for other crtcs enabled even if there are no users for them. Make the
disable timer per-crtc to avoid this issue.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 21 insertions, 19 deletions

diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index ea20c4aa1b6b..90c59a8c820f 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -140,33 +140,34 @@ static void vblank_disable_and_save(struct drm_device *dev, int crtc)
 
 static void vblank_disable_fn(unsigned long arg)
 {
-	struct drm_device *dev = (struct drm_device *)arg;
+	struct drm_vblank_crtc *vblank = (void *)arg;
+	struct drm_device *dev = vblank->dev;
 	unsigned long irqflags;
-	int i;
+	int crtc = vblank->crtc;
 
 	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[i].refcount) == 0 &&
-		    dev->vblank[i].enabled) {
-			DRM_DEBUG("disabling vblank on crtc %d\n", i);
-			vblank_disable_and_save(dev, i);
-		}
-		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+	spin_lock_irqsave(&dev->vbl_lock, irqflags);
+	if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) {
+		DRM_DEBUG("disabling vblank on crtc %d\n", crtc);
+		vblank_disable_and_save(dev, crtc);
 	}
+	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 }
 
 void drm_vblank_cleanup(struct drm_device *dev)
 {
+	int crtc;
+
 	/* Bail if the driver didn't call drm_vblank_init() */
 	if (dev->num_crtcs == 0)
 		return;
 
-	del_timer_sync(&dev->vblank_disable_timer);
-
-	vblank_disable_fn((unsigned long)dev);
+	for (crtc = 0; crtc < dev->num_crtcs; crtc++) {
+		del_timer_sync(&dev->vblank[crtc].disable_timer);
+		vblank_disable_fn((unsigned long)&dev->vblank[crtc]);
+	}
 
 	kfree(dev->vblank);
 
@@ -178,8 +179,6 @@ 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);
 	spin_lock_init(&dev->vblank_time_lock);
 
@@ -189,8 +188,13 @@ int drm_vblank_init(struct drm_device *dev, int num_crtcs)
 	if (!dev->vblank)
 		goto err;
 
-	for (i = 0; i < num_crtcs; i++)
+	for (i = 0; i < num_crtcs; i++) {
+		dev->vblank[i].dev = dev;
+		dev->vblank[i].crtc = i;
 		init_waitqueue_head(&dev->vblank[i].queue);
+		setup_timer(&dev->vblank[i].disable_timer, vblank_disable_fn,
+			    (unsigned long)&dev->vblank[i]);
+	}
 
 	DRM_INFO("Supports vblank timestamp caching Rev 2 (21.10.2013).\n");
 
@@ -900,7 +904,7 @@ void drm_vblank_put(struct drm_device *dev, int crtc)
 	/* Last user schedules interrupt disable */
 	if (atomic_dec_and_test(&dev->vblank[crtc].refcount) &&
 	    (drm_vblank_offdelay > 0))
-		mod_timer(&dev->vblank_disable_timer,
+		mod_timer(&dev->vblank[crtc].disable_timer,
 			  jiffies + ((drm_vblank_offdelay * HZ)/1000));
 }
 EXPORT_SYMBOL(drm_vblank_put);
@@ -909,8 +913,6 @@ EXPORT_SYMBOL(drm_vblank_put);
  * drm_vblank_off - disable vblank events on a CRTC
  * @dev: DRM device
  * @crtc: CRTC in question
- *
- * Caller must hold event lock.
  */
 void drm_vblank_off(struct drm_device *dev, int crtc)
 {