[Mesa-dev] [PATCH 4/5] r600g, radeonsi: Use write-combined persistent GTT mappings

[Michel Dänzer]

On 18.07.2014 20:45, Marek Olšák wrote:
> If the requirements of GL_MAP_COHERENT_BIT are satisfied, then the
> patch is okay.

AFAICT GL_MAP_COHERENT_BIT simply means the app doesn't need to call
glMemoryBarrier() to ensure coherency between access to the mapping and
GL commands. Since we don't need to do anything for glMemoryBarrier(),
GL_MAP_COHERENT_BIT doesn't make any difference for us.

That said, I think I need to add code in the kernel ensuring we always
flush the HDP cache before submitting a command stream to the hardware,
bump the minor version, and only use VRAM for streaming when the DRM
minor version is >= the bumped version.


-- 
Earthling Michel Dänzer            |                  http://www.amd.com
Libre software enthusiast          |                Mesa and X developer