From fdfc61594e6de21c23f955818ef78bcab9bafe40 Mon Sep 17 00:00:00 2001
From: Alex Deucher <alexander.deucher@amd.com>
Date: Thu, 22 Sep 2011 10:47:23 -0400
Subject: [PATCH] drm/radeon/kms: fix DDIA enable on some rs690 systems

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@amd.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
---
 drivers/gpu/drm/radeon/radeon_encoders.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/radeon/radeon_encoders.c b/drivers/gpu/drm/radeon/radeon_encoders.c
index 319d85d7e759b..13690f3eb4a4d 100644
--- a/drivers/gpu/drm/radeon/radeon_encoders.c
+++ b/drivers/gpu/drm/radeon/radeon_encoders.c
@@ -1507,7 +1507,14 @@ 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);
-- 
2.30.2