Even if the vblank period would allow it, it still seems to be problematic on some cards. bug: https://bugs.freedesktop.org/show_bug.cgi?id=96868 Signed-off-by: Alex Deucher <alexander.deucher at amd.com> --- drivers/gpu/drm/radeon/ci_dpm.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/gpu/drm/radeon/ci_dpm.c b/drivers/gpu/drm/radeon/ci_dpm.c index 7ba4508..5ced733 100644 --- a/drivers/gpu/drm/radeon/ci_dpm.c +++ b/drivers/gpu/drm/radeon/ci_dpm.c @@ -776,6 +776,12 @@ bool ci_dpm_vblank_too_short(struct radeon_device *rdev) u32 vblank_time = r600_dpm_get_vblank_time(rdev); u32 switch_limit = pi->mem_gddr5 ? 450 : 300; + /* disable mclk switching if the refresh is >120Hz, even if the + * blanking period would allow it + */ + if (r600_dpm_get_vrefresh(rdev) > 120) + return false; + if (vblank_time < switch_limit) return true; else -- 2.5.5
