Merge tag 'drm-intel-fixes-2014-06-17' of git://anongit.freedesktop.org/drm-intel...

[cascardo/linux.git] / drivers / gpu / drm / i915 / i915_irq.c

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 6f8017a..267f069 100644 (file)
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2847,10 +2847,14 @@ static int semaphore_passed(struct intel_engine_cs *ring)
        struct intel_engine_cs *signaller;
        u32 seqno, ctl;
 
-       ring->hangcheck.deadlock = true;
+       ring->hangcheck.deadlock++;
 
        signaller = semaphore_waits_for(ring, &seqno);
-       if (signaller == NULL || signaller->hangcheck.deadlock)
+       if (signaller == NULL)
+               return -1;
+
+       /* Prevent pathological recursion due to driver bugs */
+       if (signaller->hangcheck.deadlock >= I915_NUM_RINGS)
                return -1;
 
        /* cursory check for an unkickable deadlock */
@@ -2858,7 +2862,13 @@ static int semaphore_passed(struct intel_engine_cs *ring)
        if (ctl & RING_WAIT_SEMAPHORE && semaphore_passed(signaller) < 0)
                return -1;
 
-       return i915_seqno_passed(signaller->get_seqno(signaller, false), seqno);
+       if (i915_seqno_passed(signaller->get_seqno(signaller, false), seqno))
+               return 1;
+
+       if (signaller->hangcheck.deadlock)
+               return -1;
+
+       return 0;
 }
 
 static void semaphore_clear_deadlocks(struct drm_i915_private *dev_priv)
@@ -2867,7 +2877,7 @@ static void semaphore_clear_deadlocks(struct drm_i915_private *dev_priv)
        int i;
 
        for_each_ring(ring, dev_priv, i)
-               ring->hangcheck.deadlock = false;
+               ring->hangcheck.deadlock = 0;
 }
 
 static enum intel_ring_hangcheck_action