From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.
===============
commit 753b1ad4a281b0663329409d410243e91825c323 upstream.
intel_ring_cachline_align() emits MI_NOOPs until the ring tail is
aligned to a cacheline boundary.
Cc: Bjoern C <lkml@xxxxxxxxxxxx>
Cc: Alexandru DAMIAN <alexandru.damian@xxxxxxxxx>
Cc: Enrico Tagliavini <enrico.tagliavini@xxxxxxxxx>
Suggested-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
drivers/gpu/drm/i915/intel_ringbuffer.c | 21 +++++++++++++++++++++
drivers/gpu/drm/i915/intel_ringbuffer.h | 1 +
2 files changed, 22 insertions(+)
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 43719bbb2595..7507fe036b6e 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1545,6 +1545,27 @@ int intel_ring_begin(struct intel_ring_buffer *ring,
return 0;
}
+/* Align the ring tail to a cacheline boundary */
+int intel_ring_cacheline_align(struct intel_ring_buffer *ring)
+{
+ int num_dwords = (64 - (ring->tail & 63)) / sizeof(uint32_t);
+ int ret;
+
+ if (num_dwords == 0)
+ return 0;
+
+ ret = intel_ring_begin(ring, num_dwords);
+ if (ret)
+ return ret;
+
+ while (num_dwords--)
+ intel_ring_emit(ring, MI_NOOP);
+
+ intel_ring_advance(ring);
+
+ return 0;
+}
+
void intel_ring_init_seqno(struct intel_ring_buffer *ring, u32 seqno)
{
struct drm_i915_private *dev_priv = ring->dev->dev_private;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 68b1ca974d59..8eecbd28074a 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -231,6 +231,7 @@ intel_write_status_page(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);
+int __must_check intel_ring_cacheline_align(struct intel_ring_buffer *ring);
static inline void intel_ring_emit(struct intel_ring_buffer *ring,
u32 data)
{
--
1.9.0
--
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