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>

diff --git a/drivers/gpu/drm/radeon/radeon_encoders.c b/drivers/gpu/drm/radeon/radeon_encoders.c
index 319d85d..13690f3 100644 (file)
--- 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);