[Intel-gfx] [PATCH] drm/i915: Suppress busy status for engines if wedged

[Chris Wilson]

If the driver is wedged, HW state may be very inconsistent and
report that it is still busy, even though we have stopped using it. This
can lead to a double *ERROR* rather than a graceful cleanup after
wedging.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem.c        | 4 +---
 drivers/gpu/drm/i915/intel_engine_cs.c | 9 +++++++++
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 365ca4d9f63c..968bd88d01d2 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -3112,9 +3112,7 @@ i915_gem_idle_work_handler(struct work_struct *work)
 	 * Wait for last execlists context complete, but bail out in case a
 	 * new request is submitted.
 	 */
-	wait_for(READ_ONCE(dev_priv->gt.active_requests) ||
-		 intel_engines_are_idle(dev_priv),
-		 10);
+	wait_for(intel_engines_are_idle(dev_priv), 10);
 	if (READ_ONCE(dev_priv->gt.active_requests))
 		return;
 
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index ef3c62000697..156e4bc2a935 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -1111,6 +1111,15 @@ bool intel_engines_are_idle(struct drm_i915_private *dev_priv)
 	struct intel_engine_cs *engine;
 	enum intel_engine_id id;
 
+	if (READ_ONCE(dev_priv->gt.active_requests))
+		return false;
+
+	/* If the driver is wedged, HW state may be very inconsistent and
+	 * report that it is still busy, even though we have stopped using it.
+	 */
+	if (i915_terminally_wedged(&dev_priv->gpu_error))
+		return true;
+
 	for_each_engine(engine, dev_priv, id) {
 		if (!intel_engine_is_idle(engine))
 			return false;
-- 
2.11.0