[PATCH] drm/radeon/kms/atom: fix duallink on some early DCE3.2 cards

[Alex Deucher]

Certain revisions of the vbios on DCE3.2 cards have a bug
in the transmitter control table which prevents duallink from
being enabled properly on some cards.  The action switch statement
jumps to the wrong offset for the OUTPUT_ENABLE action.  The fix
is to use the ENABLE action rather than the OUTPUT_ENABLE action
on the affected cards.  In fixed version of the vbios, both
actions jump to the same offset, so the change should be safe.

Signed-off-by: Alex Deucher <alexdeucher at gmail.com>
Cc: stable at kernel.org
---
 drivers/gpu/drm/radeon/radeon_encoders.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/drivers/gpu/drm/radeon/radeon_encoders.c b/drivers/gpu/drm/radeon/radeon_encoders.c
index 175a1e3..b293487 100644
--- a/drivers/gpu/drm/radeon/radeon_encoders.c
+++ b/drivers/gpu/drm/radeon/radeon_encoders.c
@@ -1432,7 +1432,11 @@ radeon_atom_encoder_dpms(struct drm_encoder *encoder, int mode)
 	if (is_dig) {
 		switch (mode) {
 		case DRM_MODE_DPMS_ON:
-			atombios_dig_transmitter_setup(encoder, ATOM_TRANSMITTER_ACTION_ENABLE_OUTPUT, 0, 0);
+			/* some early dce3.2 boards have a bug in their transmitter control table */
+			if ((rdev->family == CHIP_RV710) || (rdev->family == CHIP_RV730))
+				atombios_dig_transmitter_setup(encoder, ATOM_TRANSMITTER_ACTION_ENABLE, 0, 0);
+			else
+				atombios_dig_transmitter_setup(encoder, ATOM_TRANSMITTER_ACTION_ENABLE_OUTPUT, 0, 0);
 			if (atombios_get_encoder_mode(encoder) == ATOM_ENCODER_MODE_DP) {
 				struct drm_connector *connector = radeon_get_connector_for_encoder(encoder);
 
-- 
1.7.1.1