[Mesa-dev] [v2] Compression support for single-sampled

Ben Widawsky ben at bwidawsk.net
Mon Feb 15 21:31:36 UTC 2016


On Thu, Feb 11, 2016 at 08:33:53PM +0200, Topi Pohjolainen wrote:
> This series enables compression for single sampled color surfaces,
> also referred to as "lossless compression". This is yet only for
> driver internal use easing pressure on memory bandwidth and caches
> when writing, blending and sampling surfaces uing gpu.
> 
> As a side effect the need for color buffer resolves after fast
> clears is also decreased. Current understanding is that sampling
> engine doesn't understand meta data (auxiliary buffer) for single
> sampled fast cleared surfaces. However, if the meta data is written
> with lossless compression enabled, even sampling engine is capable
> of reading both the color buffer and the auxiliary, and resolves
> can be omitted in those case.
> 
> The final enabling patch is dependent on earlier two-patch series
> fixing state restore mechanism in i965-meta operations.
> 
> v2 (Ben):  Use combination of msaa_layout and number of samples
>            instead of introducing explicit type for lossless
>            compression.
> 

I'm skipping 19 for now until we get through the rest.

In addition to the comments I left, 11,12,15,16,17 are:
Reviewed-by: Ben Widawsky <benjamin.widawsky at intel.com>

11: I'm not quite sold on the needs for a general flags yet, but it doesn't
really hurt afaict.
16: I'd just squash this in to 19, but I don't really care much/.


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