[Intel-gfx] [PATCH 2/6] drm/i915: kicking rings stuck on semaphores considered harmful

[Daniel Vetter]

If our semaphore logic gets confused and we have a ring stuck waiting
for one, there's a decent chance it'll just execute garbage when being
kicked. Also, kicking the ring obscures the place where the error
first occured, making error_state decoding much harder.

So drop this an let gpu reset handle this mess in a clean fashion.

In contrast, kicking rings stuck on MI_WAIT is rather harmless, at
worst there'll be a bit of screen-flickering. There's also old
broken userspace out there which needs this as a  work-around.

Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/i915_irq.c |    7 -------
 1 files changed, 0 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 2218d12..3563a2e 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1645,13 +1645,6 @@ static bool kick_ring(struct intel_ring_buffer *ring)
 		I915_WRITE_CTL(ring, tmp);
 		return true;
 	}
-	if (IS_GEN6(dev) &&
-	    (tmp & RING_WAIT_SEMAPHORE)) {
-		DRM_ERROR("Kicking stuck semaphore on %s\n",
-			  ring->name);
-		I915_WRITE_CTL(ring, tmp);
-		return true;
-	}
 	return false;
 }
 
-- 
1.7.6.4