[Intel-gfx] [PATCH 3/5] drm/i915: don't return a spurious -EIO from intel_ring_begin

[Daniel Vetter]

We have a careful logic in i915_gem_check_wedge already to asses whether
the gpu reset has been tried already and hence whether to return -EIO
or -EAGAIN.

Having this early check in intel_ring_begin doesn't buy us anything,
since we'll be calling into wait_request in the usual case already
anyway. In the corner case of not waiting for free space using the
last_retired_head we simply need to do the same check, too.

With these changes we'll only ever get an -EIO from intel_ring_begin
if the gpu has truely been declared dead.

Signed-Off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/i915_drv.h         |    1 +
 drivers/gpu/drm/i915/i915_gem.c         |    2 +-
 drivers/gpu/drm/i915/intel_ringbuffer.c |   10 ++++------
 3 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index a0c15ab..86ac9ff 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1330,6 +1330,7 @@ i915_gem_object_unpin_fence(struct drm_i915_gem_object *obj)
 
 void i915_gem_retire_requests(struct drm_device *dev);
 void i915_gem_retire_requests_ring(struct intel_ring_buffer *ring);
+int __must_check i915_gem_check_wedge(struct drm_i915_private *dev_priv);
 
 void i915_gem_reset(struct drm_device *dev);
 void i915_gem_clflush_object(struct drm_i915_gem_object *obj);
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 6a98c06..1214850 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1863,7 +1863,7 @@ i915_gem_retire_work_handler(struct work_struct *work)
 	mutex_unlock(&dev->struct_mutex);
 }
 
-static int
+int
 i915_gem_check_wedge(struct drm_i915_private *dev_priv)
 {
 	BUG_ON(!mutex_is_locked(&dev_priv->dev->struct_mutex));
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index f30a53a..1e86894 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1220,8 +1220,10 @@ int intel_wait_ring_buffer(struct intel_ring_buffer *ring, int n)
 		}
 
 		msleep(1);
-		if (atomic_read(&dev_priv->mm.wedged))
-			return -EAGAIN;
+
+		ret = i915_gem_check_wedge(dev_priv);
+		if (ret)
+			return ret;
 	} while (!time_after(jiffies, end));
 	trace_i915_ring_wait_end(ring);
 	return -EBUSY;
@@ -1230,13 +1232,9 @@ int intel_wait_ring_buffer(struct intel_ring_buffer *ring, int n)
 int intel_ring_begin(struct intel_ring_buffer *ring,
 		     int num_dwords)
 {
-	struct drm_i915_private *dev_priv = ring->dev->dev_private;
 	int n = 4*num_dwords;
 	int ret;
 
-	if (unlikely(atomic_read(&dev_priv->mm.wedged)))
-		return -EIO;
-
 	if (unlikely(ring->tail + n > ring->effective_size)) {
 		ret = intel_wrap_ring_buffer(ring);
 		if (unlikely(ret))
-- 
1.7.10