tree ba99c19682038634fece39989fef348baaebab1b
parent 7c1c7c18fc752b2a1d07597286467ef186312463
author Samuel Li <samuel.li@amd.com> 1365456347 -0400
committer Alex Deucher <alexander.deucher@amd.com> 1365517891 -0400

drm/radeon: Use direct mapping for fast fb access on RS690

This patch allows the CPU to map the stolen vram segment
directly rather than going through the PCI BAR.  This
significantly improves performance for certain workloads with
a properly patched ddx.

Use radeon.fastfb=1 to enable it (disabled by default).
Currently only supported on RS690, but support for RS780/880
and newer APUs may be added eventually.

Signed-off-by: Samuel Li <samuel.li@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>