[Mesa-dev] [PATCH 0/5] i965/gen9: Support fast clear on SRGB buffers

[Neil Roberts]

Currently fast clears are disabled on SKL with SRGB buffers because
they are not marked as losslessly compressible in the formats table.
This is less than ideal because by default the window system buffers
are created as SRGB so in practice it means an application is unlikely
to end up using fast clears except for FBOs. However unless the
application enables GL_FRAMEBUFFER_SRGB the surface format given to
the hardware is always its linear equivalent so it shouldn't actually
be a problem. The aim of this series is to make that use case work.

Sadly there is a second obstacle stopping window system buffers from
using fast clears which as that they are always x-tiled and supposedly
SKL doesn't support that. This is explicitly disabled in
intel_tiling_supports_non_msrt_mcs. However if I remove that
restriction I couldn't find any problems so it might just work to
remove it.

All of my SKL fast clear patches are in a branch here:

https://github.com/bpeel/mesa/commits/skl-fast-clear