drm/i915/ringbuffer: Write the value passed in to the tail register

This should fix the error along the reset path were we tried to clear the
tail register by setting it to 0, but were in fact setting it to the
current value and complaining when it did not reset to 0.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -119,12 +119,12 @@ render_ring_flush(struct drm_device *dev,
 	}
 }
 
-static void ring_set_tail(struct drm_device *dev,
+static void ring_write_tail(struct drm_device *dev,
 			    struct intel_ring_buffer *ring,
 			    u32 value)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
-	I915_WRITE_TAIL(ring, ring->tail);
+	I915_WRITE_TAIL(ring, value);
 }
 
 u32 intel_ring_get_active_head(struct drm_device *dev,
@@ -148,7 +148,7 @@ static int init_ring_common(struct drm_device *dev,
 	/* Stop the ring if it's running. */
 	I915_WRITE_CTL(ring, 0);
 	I915_WRITE_HEAD(ring, 0);
-	ring->set_tail(dev, ring, 0);
+	ring->write_tail(dev, ring, 0);
 
 	/* Initialize the ring. */
 	I915_WRITE_START(ring, obj_priv->gtt_offset);
@@ -729,7 +729,7 @@ void intel_ring_advance(struct drm_device *dev,
 			struct intel_ring_buffer *ring)
 {
 	ring->tail &= ring->size - 1;
-	ring->set_tail(dev, ring, ring->tail);
+	ring->write_tail(dev, ring, ring->tail);
 }
 
 static const struct intel_ring_buffer render_ring = {
@@ -738,7 +738,7 @@ static const struct intel_ring_buffer render_ring = {
 	.mmio_base		= RENDER_RING_BASE,
 	.size			= 32 * PAGE_SIZE,
 	.init			= init_render_ring,
-	.set_tail		= ring_set_tail,
+	.write_tail		= ring_write_tail,
 	.flush			= render_ring_flush,
 	.add_request		= render_ring_add_request,
 	.get_seqno		= render_ring_get_seqno,
@@ -755,7 +755,7 @@ static const struct intel_ring_buffer bsd_ring = {
 	.mmio_base		= BSD_RING_BASE,
 	.size			= 32 * PAGE_SIZE,
 	.init			= init_bsd_ring,
-	.set_tail		= ring_set_tail,
+	.write_tail		= ring_write_tail,
 	.flush			= bsd_ring_flush,
 	.add_request		= ring_add_request,
 	.get_seqno		= ring_status_page_get_seqno,
@@ -765,7 +765,7 @@ static const struct intel_ring_buffer bsd_ring = {
 };
 
 
-static void gen6_bsd_ring_set_tail(struct drm_device *dev,
+static void gen6_bsd_ring_write_tail(struct drm_device *dev,
 				     struct intel_ring_buffer *ring,
 				     u32 value)
 {
@@ -829,7 +829,7 @@ static const struct intel_ring_buffer gen6_bsd_ring = {
        .mmio_base		= GEN6_BSD_RING_BASE,
        .size			= 32 * PAGE_SIZE,
        .init			= init_bsd_ring,
-       .set_tail		= gen6_bsd_ring_set_tail,
+       .write_tail		= gen6_bsd_ring_write_tail,
        .flush			= gen6_ring_flush,
        .add_request		= ring_add_request,
        .get_seqno		= ring_status_page_get_seqno,
@@ -859,7 +859,7 @@ static const struct intel_ring_buffer gen6_blt_ring = {
        .mmio_base		= BLT_RING_BASE,
        .size			= 32 * PAGE_SIZE,
        .init			= init_ring_common,
-       .set_tail		= ring_set_tail,
+       .write_tail		= ring_write_tail,
        .flush			= gen6_ring_flush,
        .add_request		= ring_add_request,
        .get_seqno		= ring_status_page_get_seqno,

drivers/gpu/drm/i915/intel_ringbuffer.h

@@ -46,7 +46,7 @@ struct  intel_ring_buffer {
 	int		(*init)(struct drm_device *dev,
 			struct intel_ring_buffer *ring);
 
-	void		(*set_tail)(struct drm_device *dev,
+	void		(*write_tail)(struct drm_device *dev,
 				      struct intel_ring_buffer *ring,
 				      u32 value);
 	void		(*flush)(struct drm_device *dev,