[PATCH 1/2] drm/i915: Replace nondescript 'WARN_ON(!lret)' with a sensible error message

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

When a vblank wait times out in intel_atomic_wait_for_vblanks() we just
get a cryptic 'WARN_ON(!ret)' backtrace in dmesg. Repace it with
something that tells you what actually happened.

Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_display.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 4cca155376be..7bdbe4b03591 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -13523,7 +13523,7 @@ static void intel_atomic_wait_for_vblanks(struct drm_device *dev,
 					drm_crtc_vblank_count(crtc),
 				msecs_to_jiffies(50));
 
-		WARN_ON(!lret);
+		WARN(!lret, "pipe %c vblank wait timed out\n", pipe_name(pipe));
 
 		drm_crtc_vblank_put(crtc);
 	}
-- 
2.7.4