From: Ville Syrj?l? <ville.syrjala at linux.intel.com>
According to BSpec the ring head and tail pointers must not be
on the same cacheline when head > tail. The easiest way to enforce
this is to reduce the reported ring space.
Signed-off-by: Ville Syrj?l? <ville.syrjala at linux.intel.com>
---
drivers/gpu/drm/i915/i915_dma.c | 2 +-
drivers/gpu/drm/i915/intel_ringbuffer.c | 4 ++--
drivers/gpu/drm/i915/intel_ringbuffer.h | 2 +-
3 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 2cba7b4..d184727 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -168,7 +168,7 @@ void i915_kernel_lost_context(struct drm_device * dev)
ring->head = I915_READ_HEAD(ring) & HEAD_ADDR;
ring->tail = I915_READ_TAIL(ring) & TAIL_ADDR;
- ring->space = ring->head - (ring->tail + 8);
+ ring->space = ring->head - (ring->tail + 64);
if (ring->space < 0)
ring->space += ring->size;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index c828169..70a184e 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -46,7 +46,7 @@ struct pipe_control {
static inline int ring_space(struct intel_ring_buffer *ring)
{
- int space = (ring->head & HEAD_ADDR) - (ring->tail + 8);
+ int space = (ring->head & HEAD_ADDR) - (ring->tail + 64);
if (space < 0)
space += ring->size;
return space;
@@ -1163,7 +1163,7 @@ static int intel_ring_wait_request(struct intel_ring_buffer *ring, int n)
if (request->tail == -1)
continue;
- space = request->tail - (ring->tail + 8);
+ space = request->tail - (ring->tail + 64);
if (space < 0)
space += ring->size;
if (space >= n) {
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 2ea7a31..b15f896 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -187,7 +187,7 @@ void intel_cleanup_ring_buffer(struct intel_ring_buffer *ring);
int __must_check intel_wait_ring_buffer(struct intel_ring_buffer *ring, int n);
static inline int intel_wait_ring_idle(struct intel_ring_buffer *ring)
{
- return intel_wait_ring_buffer(ring, ring->size - 8);
+ return intel_wait_ring_buffer(ring, ring->size - 64);
}
int __must_check intel_ring_begin(struct intel_ring_buffer *ring, int n);
--
1.7.8.6
