drm/radeon/kms/atom: force bpc to 8 for now

Using the bpc (bits per color) specified by the monitor
can cause problems in some cases.  Until we get a better
handle on how to deal with those cases, just use a bpc of 8.

Reported-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

3 files changed, 10 insertions, 5 deletions

diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index 083b3eada001..b5ff1f7b6f7e 100644
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -588,8 +588,8 @@ static u32 atombios_adjust_pll(struct drm_crtc *crtc,
                 if (encoder->crtc == crtc) {
                         radeon_encoder = to_radeon_encoder(encoder);
                         connector = radeon_get_connector_for_encoder(encoder);
-                        if (connector && connector->display_info.bpc)
-                                bpc = connector->display_info.bpc;
+                        /* if (connector && connector->display_info.bpc)
+                                bpc = connector->display_info.bpc; */
                         encoder_mode = atombios_get_encoder_mode(encoder);
                         is_duallink = radeon_dig_monitor_is_duallink(encoder, mode->clock);
                         if ((radeon_encoder->devices & (ATOM_DEVICE_LCD_SUPPORT | ATOM_DEVICE_DFP_SUPPORT)) ||
@@ -965,7 +965,9 @@ static void atombios_crtc_set_pll(struct drm_crtc *crtc, struct drm_display_mode
                 struct radeon_connector_atom_dig *dig_connector =
                         radeon_connector->con_priv;
                 int dp_clock;
-                bpc = connector->display_info.bpc;
+
+                /* if (connector->display_info.bpc)
+                        bpc = connector->display_info.bpc; */
 
                 switch (encoder_mode) {
                 case ATOM_ENCODER_MODE_DP_MST:
diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c
index 6c62be226804..c57d85664e77 100644
--- a/drivers/gpu/drm/radeon/atombios_dp.c
+++ b/drivers/gpu/drm/radeon/atombios_dp.c
@@ -405,10 +405,13 @@ static void dp_get_adjust_train(u8 link_status[DP_LINK_STATUS_SIZE],
 /* get bpc from the EDID */
 static int convert_bpc_to_bpp(int bpc)
 {
+#if 0
         if (bpc == 0)
                 return 24;
         else
                 return bpc * 3;
+#endif
+        return 24;
 }
 
 /* get the max pix clock supported by the link rate and lane num */
diff --git a/drivers/gpu/drm/radeon/atombios_encoders.c b/drivers/gpu/drm/radeon/atombios_encoders.c
index 468b874336f9..e607c4d7dd98 100644
--- a/drivers/gpu/drm/radeon/atombios_encoders.c
+++ b/drivers/gpu/drm/radeon/atombios_encoders.c
@@ -541,7 +541,7 @@ atombios_dig_encoder_setup(struct drm_encoder *encoder, int action, int panel_mo
                 dp_clock = dig_connector->dp_clock;
                 dp_lane_count = dig_connector->dp_lane_count;
                 hpd_id = radeon_connector->hpd.hpd;
-                bpc = connector->display_info.bpc;
+                /* bpc = connector->display_info.bpc; */
         }
 
         /* no dig encoder assigned */
@@ -1159,7 +1159,7 @@ atombios_external_encoder_setup(struct drm_encoder *encoder,
                 dp_lane_count = dig_connector->dp_lane_count;
                 connector_object_id =
                         (radeon_connector->connector_object_id & OBJECT_ID_MASK) >> OBJECT_ID_SHIFT;
-                bpc = connector->display_info.bpc;
+                /* bpc = connector->display_info.bpc; */
         }
 
         memset(&args, 0, sizeof(args));