[PATCH 3.19.y-ckt 14/92] drm/radeon: adjust pll when audio is not enabled

[Kamal Mostafa]

3.19.8-ckt1 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alex Deucher <alexander.deucher at amd.com>

commit 7fe04d6fa824ccea704535a597dc417c8687f990 upstream.

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 at amd.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/gpu/drm/radeon/atombios_crtc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index 9bd5611..1afc0b4 100644
--- 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 */
-- 
1.9.1