[ 33/49] drm/radeon/atom: workaround vbios bug in transmitter table on rs880 (v2)

From: Greg Kroah-Hartman
Date: Sun Sep 29 2013 - 15:28:34 EST

3.10-stable review patch. If anyone has any objections, please let me know.


From: Alex Deucher <alexander.deucher@xxxxxxx>

commit 91f3a6aaf280294b07c05dfe606e6c27b7ba3c72 upstream.

The OUTPUT_ENABLE action jumps past the point in the coder where
the data_offset is set on certain rs780 cards. This worked
previously because the OUTPUT_ENABLE action is always called
immediately after the ENABLE action so the data_offset remained
set. In 6f8bbaf568c7f2c497558bfd04654c0b9841ad57
(drm/radeon/atom: initialize more atom interpretor elements to 0),
we explictly reset data_offset to 0 between atom calls which then
caused this to fail. The fix is to just skip calling the
OUTPUT_ENABLE action on the problematic chipsets. The ENABLE
action does the same thing and more. Ultimately, we could
probably drop the OUTPUT_ENABLE action all together on DCE3


v2: only rs880 seems to be affected

Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/gpu/drm/radeon/atombios_encoders.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/radeon/atombios_encoders.c
+++ b/drivers/gpu/drm/radeon/atombios_encoders.c
@@ -1636,8 +1636,12 @@ radeon_atom_encoder_dpms_dig(struct drm_
atombios_dig_encoder_setup(encoder, ATOM_ENABLE, 0);
atombios_dig_transmitter_setup(encoder, ATOM_TRANSMITTER_ACTION_SETUP, 0, 0);
atombios_dig_transmitter_setup(encoder, ATOM_TRANSMITTER_ACTION_ENABLE, 0, 0);
- /* some early dce3.2 boards have a bug in their transmitter control table */
- if ((rdev->family != CHIP_RV710) && (rdev->family != CHIP_RV730))
+ /* some dce3.x boards have a bug in their transmitter control table.
+ * ACTION_ENABLE_OUTPUT can probably be dropped since ACTION_ENABLE
+ * does the same thing and more.
+ */
+ if ((rdev->family != CHIP_RV710) && (rdev->family != CHIP_RV730) &&
+ (rdev->family != CHIP_RS880))
atombios_dig_transmitter_setup(encoder, ATOM_TRANSMITTER_ACTION_ENABLE_OUTPUT, 0, 0);
if (ENCODER_MODE_IS_DP(atombios_get_encoder_mode(encoder)) && connector) {

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