[ 20/82] drm/i915: Dont clobber crtc->fb when queue_flip fails

Ben Hutchings
2013-03-18T04:34:55Z

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

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

From: Ville Syrjälä <ville.syrjala@linux.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.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reported-and-Tested-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
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
@@ -7280,8 +7280,8 @@ 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;
@@ -7293,8 +7293,7 @@ static int intel_crtc_page_flip(struct d

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);
@@ -7314,9 +7313,6 @@ 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;
-
mutex_lock(&dev->struct_mutex);

/* Reference the objects for the scheduled work. */
@@ -7347,6 +7343,7 @@ static int intel_crtc_page_flip(struct d

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);