From: Thierry Reding treding@nvidia.com
If the sink is eDP and supports the alternate scrambler reset, enable it.
Signed-off-by: Thierry Reding treding@nvidia.com --- drivers/gpu/drm/drm_dp_helper.c | 11 +++++++++++ include/drm/drm_dp_helper.h | 1 + 2 files changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index e3a289793c73..76ac68bc1042 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -316,6 +316,7 @@ static void drm_dp_link_caps_reset(struct drm_dp_link_caps *caps) caps->tps3_supported = false; caps->fast_training = false; caps->channel_coding = false; + caps->alternate_scrambler_reset = false; }
void drm_dp_link_caps_copy(struct drm_dp_link_caps *dest, @@ -325,6 +326,7 @@ void drm_dp_link_caps_copy(struct drm_dp_link_caps *dest, dest->tps3_supported = src->tps3_supported; dest->fast_training = src->fast_training; dest->channel_coding = src->channel_coding; + dest->alternate_scrambler_reset = src->alternate_scrambler_reset; }
static void drm_dp_link_reset(struct drm_dp_link *link) @@ -378,6 +380,8 @@ int drm_dp_link_probe(struct drm_dp_aux *aux, struct drm_dp_link *link) static const u8 edp_revs[] = { 0x11, 0x12, 0x13, 0x14 }; u8 value;
+ link->caps.alternate_scrambler_reset = true; + err = drm_dp_dpcd_readb(aux, DP_EDP_DPCD_REV, &value); if (err < 0) return err; @@ -493,6 +497,13 @@ int drm_dp_link_configure(struct drm_dp_aux *aux, struct drm_dp_link *link) if (err < 0) return err;
+ if (link->caps.alternate_scrambler_reset) { + err = drm_dp_dpcd_writeb(aux, DP_EDP_CONFIGURATION_SET, + DP_ALTERNATE_SCRAMBLER_RESET_ENABLE); + if (err < 0) + return err; + } + return 0; } EXPORT_SYMBOL(drm_dp_link_configure); diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index 2efa6539c783..825aaf4e8c71 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -793,6 +793,7 @@ struct drm_dp_link_caps { bool tps3_supported; bool fast_training; bool channel_coding; + bool alternate_scrambler_reset; };
void drm_dp_link_caps_copy(struct drm_dp_link_caps *dest,