[PATCH] drm/radeon/kms: fix DDIA enable on some rs690 systems

[alexdeucher at gmail.com]

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

DVOOutputControl checks the value of of bios scratch reg 3
on some tables and assumes the encoder is already enabled
if the DFP2_ACTIVE bit is set.  Clear that bit so the table
sets the DDIA enable bit properly.

Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
Cc: stable at kernel.org
---
 drivers/gpu/drm/radeon/radeon_encoders.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_encoders.c b/drivers/gpu/drm/radeon/radeon_encoders.c
index 9c1fdb2..2554fe3 100644
--- a/drivers/gpu/drm/radeon/radeon_encoders.c
+++ b/drivers/gpu/drm/radeon/radeon_encoders.c
@@ -1505,7 +1505,14 @@ radeon_atom_encoder_dpms(struct drm_encoder *encoder, int mode)
 		switch (mode) {
 		case DRM_MODE_DPMS_ON:
 			args.ucAction = ATOM_ENABLE;
-			atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
+			/* workaround for DVOOutputControl on some RS690 systems */
+			if (radeon_encoder->encoder_id == ENCODER_OBJECT_ID_INTERNAL_DDI) {
+				u32 reg = RREG32(RADEON_BIOS_3_SCRATCH);
+				WREG32(RADEON_BIOS_3_SCRATCH, reg & ~ATOM_S3_DFP2I_ACTIVE);
+				atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
+				WREG32(RADEON_BIOS_3_SCRATCH, reg);
+			} else
+				atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
 			if (radeon_encoder->devices & (ATOM_DEVICE_LCD_SUPPORT)) {
 				args.ucAction = ATOM_LCD_BLON;
 				atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
-- 
1.7.1.1