linux-kernel - [PATCH] drm/i915: fix vblank wait test condition

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Message-ID: <20100824113116.249c13b4@virtuousgeek.org>
Date:	Tue, 24 Aug 2010 11:31:16 -0700
From:	Jesse Barnes <jbarnes@...tuousgeek.org>
To:	intel-gfx@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
	torvalds@...ux-foundation.org
Subject: [PATCH] drm/i915: fix vblank wait test condition

When converting this to the new wait_for macro I inverted the wait
condition, which causes all sorts of problems.  So correct it to fix
several failures caused by the bad wait (flickering, bad output
detection, tearing, etc.).

Reviewed-by: Chris Wilson <chris@...is-wilson.co.uk>
Tested-by: Sitsofe Wheeler <sitsofe@...oo.com>
Signed-off-by: Jesse Barnes <jbarnes@...tuousgeek.org>
---
 drivers/gpu/drm/i915/intel_display.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 6ccb797..dd90b80 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -992,7 +992,7 @@ void intel_wait_for_vblank(struct drm_device *dev, int pipe)
 
 	/* Wait for vblank interrupt bit to set */
 	if (wait_for((I915_READ(pipestat_reg) &
-		      PIPE_VBLANK_INTERRUPT_STATUS) == 0,
+		      PIPE_VBLANK_INTERRUPT_STATUS),
 		     50, 0))
 		DRM_DEBUG_KMS("vblank wait timed out\n");
 }
-- 
1.6.3.3

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