On Mon, Dec 03, 2012 at 06:43:32PM +0200, ville.syrjala at linux.intel.com wrote: > From: Ville Syrj?l? <ville.syrjala at 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 > > v3: s/64/I915_RING_FREE_SPACE, and add the BSpec information to the code > > Signed-off-by: Ville Syrj?l? <ville.syrjala at linux.intel.com> > Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk> Picked up for -fixes, thanks for the patch. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch
