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

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.

Reported-and-tested-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Alex Deucher <alexdeucher@gmail.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 f55b64c..012f802 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_encoders.c
+++ b/drivers/gpu/drm/radeon/radeon_encoders.c
@@ -1431,7 +1431,11 @@ 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);