[ 142/171 ] drm/i915: Dont clobber crtc->fb when queue_flip fails

[Steven Rostedt]

3.6.11.2 stable review patch.
If anyone has any objections, please let me know.

------------------

From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@xxxxxxxxxxxxxxx>

[ Upstream commit 4a35f83b2b7c6aae3fc0d1c4554fdc99dc33ad07 ]

Restore crtc->fb to the old framebuffer if queue_flip fails.

While at it, kill the pointless intel_fb temp variable.

v2: Update crtc->fb before queue_flip and restore it back
    after a failure.

Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Reported-and-Tested-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
 drivers/gpu/drm/i915/intel_display.c |   11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 0777c79..379abcb 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6459,8 +6459,8 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc,
 {
 	struct drm_device *dev = crtc->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct intel_framebuffer *intel_fb;
-	struct drm_i915_gem_object *obj;
+	struct drm_framebuffer *old_fb = crtc->fb;
+	struct drm_i915_gem_object *obj = to_intel_framebuffer(fb)->obj;
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	struct intel_unpin_work *work;
 	unsigned long flags;
@@ -6485,8 +6485,7 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc,
 
 	work->event = event;
 	work->dev = crtc->dev;
-	intel_fb = to_intel_framebuffer(crtc->fb);
-	work->old_fb_obj = intel_fb->obj;
+	work->old_fb_obj = to_intel_framebuffer(old_fb)->obj;
 	INIT_WORK(&work->work, intel_unpin_work_fn);
 
 	ret = drm_vblank_get(dev, intel_crtc->pipe);
@@ -6506,9 +6505,6 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc,
 	intel_crtc->unpin_work = work;
 	spin_unlock_irqrestore(&dev->event_lock, flags);
 
-	intel_fb = to_intel_framebuffer(fb);
-	obj = intel_fb->obj;
-
 	ret = i915_mutex_lock_interruptible(dev);
 	if (ret)
 		goto cleanup;
@@ -6542,6 +6538,7 @@ static int intel_crtc_page_flip(struct drm_crtc *crtc,
 
 cleanup_pending:
 	atomic_sub(1 << intel_crtc->plane, &work->old_fb_obj->pending_flip);
+	crtc->fb = old_fb;
 	drm_gem_object_unreference(&work->old_fb_obj->base);
 	drm_gem_object_unreference(&obj->base);
 	mutex_unlock(&dev->struct_mutex);
-- 
1.7.10.4


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/