The patch below does not apply to the 3.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From a0d036b074b4a5a933e37fcb9bdd6b3cc80a0387 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Date: Sat, 19 Jul 2014 12:40:42 +0100
Subject: [PATCH] drm/i915: Reorder the semaphore deadlock check, again
commit 4be173813e57c7298103a83155c2391b5b167b4c
Author: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Date: Fri Jun 6 10:22:29 2014 +0100
drm/i915: Reorder semaphore deadlock check
did the majority of the work, but it missed one crucial detail:
The check for the unkickable deadlock on this ring must come after the
check whether the ring that we are waiting on has already passed its
target seqno.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=80709
Tested-by: Stefan Huber <shuber@xxxxxxxx>
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 267f069765ad..c05c84f3f091 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2845,7 +2845,7 @@ static int semaphore_passed(struct intel_engine_cs *ring)
{
struct drm_i915_private *dev_priv = ring->dev->dev_private;
struct intel_engine_cs *signaller;
- u32 seqno, ctl;
+ u32 seqno;
ring->hangcheck.deadlock++;
@@ -2857,15 +2857,12 @@ static int semaphore_passed(struct intel_engine_cs *ring)
if (signaller->hangcheck.deadlock >= I915_NUM_RINGS)
return -1;
- /* cursory check for an unkickable deadlock */
- ctl = I915_READ_CTL(signaller);
- if (ctl & RING_WAIT_SEMAPHORE && semaphore_passed(signaller) < 0)
- return -1;
-
if (i915_seqno_passed(signaller->get_seqno(signaller, false), seqno))
return 1;
- if (signaller->hangcheck.deadlock)
+ /* cursory check for an unkickable deadlock */
+ if (I915_READ_CTL(signaller) & RING_WAIT_SEMAPHORE &&
+ semaphore_passed(signaller) < 0)
return -1;
return 0;
--
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