[Intel-gfx] [PATCH] drm/i915: Try to stop rings before reset

[Daniel Vetter]

This seems to make the hard machine hangs provoked by running
gem_reset_stats tests a lot less likely. At least on my snb here.

v2: Don't DRM_ERROR when a reset is in progress in the stop_ring
function.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=74100
Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/intel_ringbuffer.c | 13 ++++++++-----
 drivers/gpu/drm/i915/intel_ringbuffer.h |  1 +
 drivers/gpu/drm/i915/intel_uncore.c     |  7 +++++++
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index ab22d70733bf..e8ca1dcb6a45 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -448,14 +448,17 @@ static void ring_setup_phys_status_page(struct intel_ring_buffer *ring)
 	I915_WRITE(HWS_PGA, addr);
 }
 
-static bool stop_ring(struct intel_ring_buffer *ring)
+bool __intel_stop_ring_buffer(struct intel_ring_buffer *ring)
 {
 	struct drm_i915_private *dev_priv = to_i915(ring->dev);
 
 	if (!IS_GEN2(ring->dev)) {
 		I915_WRITE_MODE(ring, _MASKED_BIT_ENABLE(STOP_RING));
 		if (wait_for_atomic((I915_READ_MODE(ring) & MODE_IDLE) != 0, 1000)) {
-			DRM_ERROR("%s :timed out trying to stop ring\n", ring->name);
+			if (!i915_reset_in_progress(&dev_priv->gpu_error)) {
+				DRM_ERROR("%s :timed out trying to stop ring\n",
+					  ring->name);
+			}
 			return false;
 		}
 	}
@@ -481,7 +484,7 @@ static int init_ring_common(struct intel_ring_buffer *ring)
 
 	gen6_gt_force_wake_get(dev_priv, FORCEWAKE_ALL);
 
-	if (!stop_ring(ring)) {
+	if (!__intel_stop_ring_buffer(ring)) {
 		/* G45 ring initialization often fails to reset head to zero */
 		DRM_DEBUG_KMS("%s head not reset to zero "
 			      "ctl %08x head %08x tail %08x start %08x\n",
@@ -491,7 +494,7 @@ static int init_ring_common(struct intel_ring_buffer *ring)
 			      I915_READ_TAIL(ring),
 			      I915_READ_START(ring));
 
-		if (!stop_ring(ring)) {
+		if (!__intel_stop_ring_buffer(ring)) {
 			DRM_ERROR("failed to set %s head to zero "
 				  "ctl %08x head %08x tail %08x start %08x\n",
 				  ring->name,
@@ -2338,5 +2341,5 @@ intel_stop_ring_buffer(struct intel_ring_buffer *ring)
 		DRM_ERROR("failed to quiesce %s whilst cleaning up: %d\n",
 			  ring->name, ret);
 
-	stop_ring(ring);
+	__intel_stop_ring_buffer(ring);
 }
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 13e398f17fb2..f3c25bd5c68d 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -266,6 +266,7 @@ intel_write_status_page(struct intel_ring_buffer *ring,
 #define I915_GEM_HWS_SCRATCH_ADDR (I915_GEM_HWS_SCRATCH_INDEX << MI_STORE_DWORD_INDEX_SHIFT)
 
 void intel_stop_ring_buffer(struct intel_ring_buffer *ring);
+bool __intel_stop_ring_buffer(struct intel_ring_buffer *ring);
 void intel_cleanup_ring_buffer(struct intel_ring_buffer *ring);
 
 int __must_check intel_ring_begin(struct intel_ring_buffer *ring, int n);
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index 76dc185793ce..18d41d04cbd8 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -1034,6 +1034,13 @@ static int gen6_do_reset(struct drm_device *dev)
 
 int intel_gpu_reset(struct drm_device *dev)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_ring_buffer *ring;
+	int i;
+
+	for_each_ring(ring, dev_priv, i)
+		__intel_stop_ring_buffer(ring);
+
 	switch (INTEL_INFO(dev)->gen) {
 	case 8:
 	case 7:
-- 
1.8.1.4