drm/radeon: adjust pll when audio is not enabled

Fixes display problems with some monitors when audio
is not enabled.

Bugs:
https://bugs.freedesktop.org/show_bug.cgi?id=89505
https://bugzilla.kernel.org/show_bug.cgi?id=94171
Plus several reports on IRC.

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

diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index dac78ad24b31558aa53d917fb802865b6a122b61..42b2ea3fdcf3584680235e6d5cab14942f7f84b1 100644 (file)
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -580,6 +580,9 @@ static u32 atombios_adjust_pll(struct drm_crtc *crtc,
                else
                        radeon_crtc->pll_flags |= RADEON_PLL_PREFER_LOW_REF_DIV;
 
+               /* if there is no audio, set MINM_OVER_MAXP  */
+               if (!drm_detect_monitor_audio(radeon_connector_edid(connector)))
+                       radeon_crtc->pll_flags |= RADEON_PLL_PREFER_MINM_OVER_MAXP;
                if (rdev->family < CHIP_RV770)
                        radeon_crtc->pll_flags |= RADEON_PLL_PREFER_MINM_OVER_MAXP;
                /* use frac fb div on APUs */