diff mbox

[1080/1094] drm/i915: Reorder the semaphore deadlock check, again

Message ID 1413889294-31328-1081-git-send-email-dheerajx.s.jamwal@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Dheeraj Jamwal Oct. 21, 2014, 11:01 a.m. UTC 
From: Chris Wilson <chris@chris-wilson.co.uk>

commit 4be173813e57c7298103a83155c2391b5b167b4c
Author: Chris Wilson <chris@chris-wilson.co.uk>
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@sthu.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit a0d036b074b4a5a933e37fcb9bdd6b3cc80a0387)

Signed-off-by: Dheeraj Jamwal <dheerajx.s.jamwal@intel.com>
---
 drivers/gpu/drm/i915/i915_irq.c |   11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 69aaa11..b7131ee 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;