drm/i915: Handle ringbuffer stalls when flushing

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_gem.c

@@ -2148,7 +2148,7 @@ i915_gem_flush_ring(struct drm_device *dev,
 		    uint32_t invalidate_domains,
 		    uint32_t flush_domains)
 {
-	ring->flush(ring, invalidate_domains, flush_domains);
+	if (ring->flush(ring, invalidate_domains, flush_domains) == 0)
 		i915_gem_process_flushing_list(dev, flush_domains, ring);
 }
 

drivers/gpu/drm/i915/i915_gem_execbuffer.c

@@ -924,7 +924,7 @@ i915_gem_execbuffer_retire_commands(struct drm_device *dev,
 				    struct intel_ring_buffer *ring)
 {
 	struct drm_i915_gem_request *request;
-	u32 flush_domains;
+	u32 invalidate;
 
 	/*
 	 * Ensure that the commands in the batch buffer are
@@ -932,11 +932,13 @@ i915_gem_execbuffer_retire_commands(struct drm_device *dev,
 	 *
 	 * The sampler always gets flushed on i965 (sigh).
 	 */
-	flush_domains = 0;
+	invalidate = I915_GEM_DOMAIN_COMMAND;
 	if (INTEL_INFO(dev)->gen >= 4)
-		flush_domains |= I915_GEM_DOMAIN_SAMPLER;
-
-	ring->flush(ring, I915_GEM_DOMAIN_COMMAND, flush_domains);
+		invalidate |= I915_GEM_DOMAIN_SAMPLER;
+	if (ring->flush(ring, invalidate, 0)) {
+		i915_gem_next_request_seqno(dev, ring);
+		return;
+	}
 
 	/* Add a breadcrumb for the completion of the batch buffer */
 	request = kzalloc(sizeof(*request), GFP_KERNEL);

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -48,7 +48,7 @@ static u32 i915_gem_get_seqno(struct drm_device *dev)
 	return seqno;
 }
 
-static void
+static int
 render_ring_flush(struct intel_ring_buffer *ring,
 		  u32	invalidate_domains,
 		  u32	flush_domains)
@@ -56,6 +56,7 @@ render_ring_flush(struct intel_ring_buffer *ring,
 	struct drm_device *dev = ring->dev;
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	u32 cmd;
+	int ret;
 
 #if WATCH_EXEC
 	DRM_INFO("%s: invalidate %08x flush %08x\n", __func__,
@@ -116,12 +117,16 @@ render_ring_flush(struct intel_ring_buffer *ring,
 #if WATCH_EXEC
 		DRM_INFO("%s: queue flush %08x to ring\n", __func__, cmd);
 #endif
-		if (intel_ring_begin(ring, 2) == 0) {
+		ret = intel_ring_begin(ring, 2);
+		if (ret)
+			return ret;
+
 		intel_ring_emit(ring, cmd);
 		intel_ring_emit(ring, MI_NOOP);
 		intel_ring_advance(ring);
 	}
-	}
+
+	return 0;
 }
 
 static void ring_write_tail(struct intel_ring_buffer *ring,
@@ -534,19 +539,24 @@ void intel_ring_setup_status_page(struct intel_ring_buffer *ring)
 	POSTING_READ(mmio);
 }
 
-static void
+static int
 bsd_ring_flush(struct intel_ring_buffer *ring,
 	       u32     invalidate_domains,
 	       u32     flush_domains)
 {
+	int ret;
+
 	if ((flush_domains & I915_GEM_DOMAIN_RENDER) == 0)
-		return;
+		return 0;
+
+	ret = intel_ring_begin(ring, 2);
+	if (ret)
+		return ret;
 
-	if (intel_ring_begin(ring, 2) == 0) {
 	intel_ring_emit(ring, MI_FLUSH);
 	intel_ring_emit(ring, MI_NOOP);
 	intel_ring_advance(ring);
-	}
+	return 0;
 }
 
 static int
@@ -980,20 +990,25 @@ static void gen6_bsd_ring_write_tail(struct intel_ring_buffer *ring,
 	       GEN6_BSD_SLEEP_PSMI_CONTROL_RC_ILDL_MESSAGE_ENABLE);
 }
 
-static void gen6_ring_flush(struct intel_ring_buffer *ring,
+static int gen6_ring_flush(struct intel_ring_buffer *ring,
 			   u32 invalidate_domains,
 			   u32 flush_domains)
 {
+	int ret;
+
 	if ((flush_domains & I915_GEM_DOMAIN_RENDER) == 0)
-		return;
+		return 0;
+
+	ret = intel_ring_begin(ring, 4);
+	if (ret)
+		return ret;
 
-	if (intel_ring_begin(ring, 4) == 0) {
 	intel_ring_emit(ring, MI_FLUSH_DW);
 	intel_ring_emit(ring, 0);
 	intel_ring_emit(ring, 0);
 	intel_ring_emit(ring, 0);
 	intel_ring_advance(ring);
-	}
+	return 0;
 }
 
 static int
@@ -1122,20 +1137,25 @@ static int blt_ring_begin(struct intel_ring_buffer *ring,
 		return intel_ring_begin(ring, 4);
 }
 
-static void blt_ring_flush(struct intel_ring_buffer *ring,
+static int blt_ring_flush(struct intel_ring_buffer *ring,
 			   u32 invalidate_domains,
 			   u32 flush_domains)
 {
+	int ret;
+
 	if ((flush_domains & I915_GEM_DOMAIN_RENDER) == 0)
-		return;
+		return 0;
+
+	ret = blt_ring_begin(ring, 4);
+	if (ret)
+		return ret;
 
-	if (blt_ring_begin(ring, 4) == 0) {
 	intel_ring_emit(ring, MI_FLUSH_DW);
 	intel_ring_emit(ring, 0);
 	intel_ring_emit(ring, 0);
 	intel_ring_emit(ring, 0);
 	intel_ring_advance(ring);
-	}
+	return 0;
 }
 
 static void blt_ring_cleanup(struct intel_ring_buffer *ring)

drivers/gpu/drm/i915/intel_ringbuffer.h

@@ -63,7 +63,7 @@ struct  intel_ring_buffer {
 
 	void		(*write_tail)(struct intel_ring_buffer *ring,
 				      u32 value);
-	void		(*flush)(struct intel_ring_buffer *ring,
+	int __must_check (*flush)(struct intel_ring_buffer *ring,
 				  u32	invalidate_domains,
 				  u32	flush_domains);
 	int		(*add_request)(struct intel_ring_buffer *ring,