drm/radeon/kms: fix DVO setup on some r4xx chips

Some r4xx chips have the wrong frev in the
DVOEncoderControl table.  It should always be 1
on r4xx.  Fixes modesetting on DVO on r4xx chips
with the bad frev.

Reported by twied on #radeon.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/radeon/atombios_encoders.c b/drivers/gpu/drm/radeon/atombios_encoders.c
index e607c4d..2d39f99 100644 (file)
--- a/drivers/gpu/drm/radeon/atombios_encoders.c
+++ b/drivers/gpu/drm/radeon/atombios_encoders.c
@@ -230,6 +230,10 @@ atombios_dvo_setup(struct drm_encoder *encoder, int action)
        if (!atom_parse_cmd_header(rdev->mode_info.atom_context, index, &frev, &crev))
                return;
 
+       /* some R4xx chips have the wrong frev */
+       if (rdev->family <= CHIP_RV410)
+               frev = 1;
+
        switch (frev) {
        case 1:
                switch (crev) {