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Commit b3f5e732 authored by Chris Wilson's avatar Chris Wilson Committed by Dave Airlie
Browse files

drm: Correct unbalanced drm_vblank_put() during mode setting. 



The first time we install a mode, the vblank will be disabled for a pipe
and so drm_vblank_get() in drm_vblank_pre_modeset() will fail. As we
unconditionally call drm_vblank_put() afterwards, the vblank reference
counter becomes unbalanced.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Acked-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: default avatarDave Airlie <airlied@linux.ie>
parent 7bec756c

drivers/gpu/drm/drm_irq.c

+10 −4
Original line number Diff line number Diff line
@@ -435,6 +435,8 @@ EXPORT_SYMBOL(drm_vblank_get); 
 */

void drm_vblank_put(struct drm_device *dev, int crtc)

{

	BUG_ON (atomic_read (&dev->vblank_refcount[crtc]) == 0);



	/* Last user schedules interrupt disable */

	if (atomic_dec_and_test(&dev->vblank_refcount[crtc]))

		mod_timer(&dev->vblank_disable_timer, jiffies + 5*DRM_HZ);
@@ -460,8 +462,9 @@ void drm_vblank_pre_modeset(struct drm_device *dev, int crtc) 
	 * so that interrupts remain enabled in the interim.

	 */

	if (!dev->vblank_inmodeset[crtc]) {

		dev->vblank_inmodeset[crtc] = 1;

		drm_vblank_get(dev, crtc);

		dev->vblank_inmodeset[crtc] = 0x1;

		if (drm_vblank_get(dev, crtc) == 0)

			dev->vblank_inmodeset[crtc] |= 0x2;

	}

}

EXPORT_SYMBOL(drm_vblank_pre_modeset);
@@ -473,9 +476,12 @@ void drm_vblank_post_modeset(struct drm_device *dev, int crtc) 
	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);



		if (dev->vblank_inmodeset[crtc] & 0x2)

			drm_vblank_put(dev, crtc);



		dev->vblank_inmodeset[crtc] = 0;

	}

}

EXPORT_SYMBOL(drm_vblank_post_modeset);