drm/i915: Clear execlist port[] before updating seqno on wedging

When we wedge the device, we clear out the in-flight requests and
advance the breadcrumb to indicate they are complete. However, the
breadcrumb advance includes an assert that the engine is idle, so that
advancement needs to be the last step to ensure we pass our own sanity
checks.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170721123238.16428-7-chris@chris-wilson.co.ukSigned-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_gem.c

@@ -3051,13 +3051,6 @@ static void engine_set_wedged(struct intel_engine_cs *engine)
 			dma_fence_set_error(&request->fence, -EIO);
 	spin_unlock_irqrestore(&engine->timeline->lock, flags);
 
-	/* Mark all pending requests as complete so that any concurrent
-	 * (lockless) lookup doesn't try and wait upon the request as we
-	 * reset it.
-	 */
-	intel_engine_init_global_seqno(engine,
-				       intel_engine_last_submit(engine));
-
 	/*
 	 * Clear the execlists queue up before freeing the requests, as those
 	 * are the ones that keep the context and ringbuffer backing objects
@@ -3086,6 +3079,13 @@ static void engine_set_wedged(struct intel_engine_cs *engine)
 		 */
 		clear_bit(ENGINE_IRQ_EXECLIST, &engine->irq_posted);
 	}
+
+	/* Mark all pending requests as complete so that any concurrent
+	 * (lockless) lookup doesn't try and wait upon the request as we
+	 * reset it.
+	 */
+	intel_engine_init_global_seqno(engine,
+				       intel_engine_last_submit(engine));
 }
 
 static int __i915_gem_set_wedged_BKL(void *data)