| Message ID | 1354041298-18898-2-git-send-email-ville.syrjala@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Nov 27, 2012 at 08:34:55PM +0200, ville.syrjala@linux.intel.com wrote: > From: Ville Syrjälä <ville.syrjala@linux.intel.com> > > From BSpec: > "If the Ring Buffer Head Pointer and the Tail Pointer are on the same > cacheline, the Head Pointer must not be greater than the Tail > Pointer." > > The easiest way to enforce this is to reduce the reported ring space. > > References: > Gen2 BSpec "1. Programming Environment" / "1.4.4.6 Ring Buffer Use" > Gen3 BSpec "vol1c Memory Interface Functions" / "2.3.4.5 Ring Buffer Use" > Gen4+ BSpec "vol1c Memory Interface and Command Stream" / "5.3.4.5 Ring Buffer Use" > > v2: Include the exact BSpec references in the description > > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Another small bikeshed for this one: Less magic numbers with #define RING_FREE_SPACE 64 -Daniel > --- > 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 86b93b2..79089aa 100644 > --- a/drivers/gpu/drm/i915/i915_dma.c > +++ b/drivers/gpu/drm/i915/i915_dma.c > @@ -141,7 +141,7 @@ 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 b0a83ce..cf11f8a 100644 > --- a/drivers/gpu/drm/i915/intel_ringbuffer.c > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c > @@ -45,7 +45,7 @@ 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; > @@ -1260,7 +1260,7 @@ 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 5af65b8..2f6d9b1 100644 > --- a/drivers/gpu/drm/i915/intel_ringbuffer.h > +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h > @@ -191,7 +191,7 @@ 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 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
On Wed, Nov 28, 2012 at 09:45:46PM +0100, Daniel Vetter wrote: > On Tue, Nov 27, 2012 at 08:34:55PM +0200, ville.syrjala@linux.intel.com wrote: > > From: Ville Syrjälä <ville.syrjala@linux.intel.com> > > > > From BSpec: > > "If the Ring Buffer Head Pointer and the Tail Pointer are on the same > > cacheline, the Head Pointer must not be greater than the Tail > > Pointer." > > > > The easiest way to enforce this is to reduce the reported ring space. > > > > References: > > Gen2 BSpec "1. Programming Environment" / "1.4.4.6 Ring Buffer Use" > > Gen3 BSpec "vol1c Memory Interface Functions" / "2.3.4.5 Ring Buffer Use" > > Gen4+ BSpec "vol1c Memory Interface and Command Stream" / "5.3.4.5 Ring Buffer Use" > > > > v2: Include the exact BSpec references in the description > > > > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > > Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> > > Another small bikeshed for this one: Less magic numbers with > > #define RING_FREE_SPACE 64 Can do. And since the number will only appear in one place, I think I'll stick the BSpec references into a comment above it.
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c index 86b93b2..79089aa 100644 --- a/drivers/gpu/drm/i915/i915_dma.c +++ b/drivers/gpu/drm/i915/i915_dma.c @@ -141,7 +141,7 @@ 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 b0a83ce..cf11f8a 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.c +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c @@ -45,7 +45,7 @@ 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; @@ -1260,7 +1260,7 @@ 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 5af65b8..2f6d9b1 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.h +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h @@ -191,7 +191,7 @@ 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);