linux-kernel - [ 089/124] drm/i915: Dont clobber crtc->fb when queue

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Date:	Tue,  2 Apr 2013 15:11:11 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org,
	Ville Syrjälä 
	<ville.syrjala@...ux.intel.com>,
	Chris Wilson <chris@...is-wilson.co.uk>,
	Daniel Vetter <daniel.vetter@...ll.ch>,
	Lingzhu Xiang <lxiang@...hat.com>,
	CAI Qian <caiqian@...hat.com>
Subject: [ 089/124] drm/i915: Dont clobber crtc->fb when queue_flip fails

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

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

From: Ville Syrjälä <ville.syrjala@...ux.intel.com>

commit 4a35f83b2b7c6aae3fc0d1c4554fdc99dc33ad07 upstream.

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.

Backported for 3.8-stable. Restored an atomic_sub removed
in 3.9 ca9c46.

Signed-off-by: Ville Syrjälä <ville.syrjala@...ux.intel.com>
Reviewed-by: Chris Wilson <chris@...is-wilson.co.uk>
Reported-and-Tested-by: Mika Kuoppala <mika.kuoppala@...el.com>
Signed-off-by: Daniel Vetter <daniel.vetter@...ll.ch>
Signed-off-by: Lingzhu Xiang <lxiang@...hat.com>
Reviewed-by: CAI Qian <caiqian@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/gpu/drm/i915/intel_display.c |   11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -7420,8 +7420,8 @@ static int intel_crtc_page_flip(struct d
 {
 	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;
@@ -7446,8 +7446,7 @@ static int intel_crtc_page_flip(struct d
 
 	work->event = event;
 	work->crtc = crtc;
-	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);
@@ -7467,9 +7466,6 @@ static int intel_crtc_page_flip(struct d
 	intel_crtc->unpin_work = work;
 	spin_unlock_irqrestore(&dev->event_lock, flags);
 
-	intel_fb = to_intel_framebuffer(fb);
-	obj = intel_fb->obj;
-
 	if (atomic_read(&intel_crtc->unpin_work_count) >= 2)
 		flush_workqueue(dev_priv->wq);
 
@@ -7507,6 +7503,7 @@ static int intel_crtc_page_flip(struct d
 
 cleanup_pending:
 	atomic_dec(&intel_crtc->unpin_work_count);
+	crtc->fb = old_fb;
 	atomic_sub(1 << intel_crtc->plane, &work->old_fb_obj->pending_flip);
 	drm_gem_object_unreference(&work->old_fb_obj->base);
 	drm_gem_object_unreference(&obj->base);


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