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@chris-wilson.co.uk>
Tested-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 23157e1..11a3394 100644 (file)
--- 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");
 }