[PATCH v2 16/21] drm/dp: Set channel coding on link configuration

[Thierry Reding]

From: Thierry Reding <treding at nvidia.com>

Make use of ANSI 8B/10B channel coding if the DisplayPort sink supports
it.

Signed-off-by: Thierry Reding <treding at nvidia.com>
---
 drivers/gpu/drm/drm_dp_helper.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index f1f3705fade9..f51a5595ebc0 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -519,7 +519,7 @@ EXPORT_SYMBOL(drm_dp_link_power_down);
  */
 int drm_dp_link_configure(struct drm_dp_aux *aux, struct drm_dp_link *link)
 {
-	u8 values[2];
+	u8 values[2], value = 0;
 	int err;
 
 	values[0] = drm_dp_link_rate_to_bw_code(link->rate);
@@ -532,6 +532,13 @@ int drm_dp_link_configure(struct drm_dp_aux *aux, struct drm_dp_link *link)
 	if (err < 0)
 		return err;
 
+	if (link->caps.channel_coding)
+		value = DP_SET_ANSI_8B10B;
+
+	err = drm_dp_dpcd_writeb(aux, DP_MAIN_LINK_CHANNEL_CODING_SET, value);
+	if (err < 0)
+		return err;
+
 	return 0;
 }
 EXPORT_SYMBOL(drm_dp_link_configure);
-- 
2.22.0