drm/i915: Ignore valid but unknown semaphores

If we find a ring waiting on a semaphore for another assigned but not yet
emitted request, treat it as valid and waiting.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160909131201.16673-18-chris@chris-wilson.co.uk

1 files changed, 6 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index ef2d40278191..b76d45d91a84 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2831,10 +2831,10 @@ semaphore_wait_to_signaller_ring(struct intel_engine_cs *engine, u32 ipehr,
                 }
         }
 
-        DRM_ERROR("No signaller ring found for ring %i, ipehr 0x%08x, offset 0x%016llx\n",
-                  engine->id, ipehr, offset);
+        DRM_DEBUG_DRIVER("No signaller ring found for ring %i, ipehr 0x%08x, offset 0x%016llx\n",
+                         engine->id, ipehr, offset);
 
-        return NULL;
+        return ERR_PTR(-ENODEV);
 }
 
 static struct intel_engine_cs *
@@ -2922,6 +2922,9 @@ static int semaphore_passed(struct intel_engine_cs *engine)
         if (signaller == NULL)
                 return -1;
 
+        if (IS_ERR(signaller))
+                return 0;
+
         /* Prevent pathological recursion due to driver bugs */
         if (signaller->hangcheck.deadlock >= I915_NUM_ENGINES)
                 return -1;