drm/radeon/ci: disable mclk switching for high refresh rates (v2)

Even if the vblank period would allow it, it still seems to
be problematic on some cards.

v2: fix logic inversion (Nils)

bug: https://bugs.freedesktop.org/show_bug.cgi?id=96868

Cc: stable@vger.kernel.org
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/radeon/ci_dpm.c b/drivers/gpu/drm/radeon/ci_dpm.c
index 7ba4508..ea36dc4 100644 (file)
--- 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 true;
+
        if (vblank_time < switch_limit)
                return true;
        else