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Commit a0d036b0 authored by Chris Wilson's avatar Chris Wilson Committed by Daniel Vetter
Browse files

drm/i915: Reorder the semaphore deadlock check, again 

commit 4be17381
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: default avatarStefan Huber <shuber@sthu.org>
Signed-off-by: default avatarChris 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: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 9a3c4145

drivers/gpu/drm/i915/i915_irq.c

+4 −7
Original line number Diff line number Diff line
@@ -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;