drm/radeon/dpm: disable mclk switching on desktop RV770
Mclk switching doesn't seem to work reliably on these
cards. Most RV770 boards specify the same mclk for all
performance levels anyway so in most cases, this has
no affect.
Bug:
https://bugs.freedesktop.org/show_bug.cgi?id=73067
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/gpu/drm/radeon/rv770_dpm.c b/drivers/gpu/drm/radeon/rv770_dpm.c
index cb730cd..80c595a 100644
--- a/drivers/gpu/drm/radeon/rv770_dpm.c
+++ b/drivers/gpu/drm/radeon/rv770_dpm.c
@@ -2536,6 +2536,12 @@
(rdev->pdev->subsystem_device == 0x1c42))
switch_limit = 200;
+ /* RV770 */
+ /* mclk switching doesn't seem to work reliably on desktop RV770s */
+ if ((rdev->family == CHIP_RV770) &&
+ !(rdev->flags & RADEON_IS_MOBILITY))
+ switch_limit = 0xffffffff; /* disable mclk switching */
+
if (vblank_time < switch_limit)
return true;
else