From: Thierry Reding treding@nvidia.com
Store the AUX read interval from DPCD, so that it can be used to wait for the durations given in the specification during link training.
Signed-off-by: Thierry Reding treding@nvidia.com --- drivers/gpu/drm/drm_dp_helper.c | 4 ++++ include/drm/drm_dp_helper.h | 17 +++++++++++++++++ 2 files changed, 21 insertions(+)
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 76ac68bc1042..da519acfeba7 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -339,6 +339,7 @@ static void drm_dp_link_reset(struct drm_dp_link *link) link->max_lanes = 0;
drm_dp_link_caps_reset(&link->caps); + link->aux_rd_interval = 0; link->edp = 0;
link->rate = 0; @@ -392,6 +393,9 @@ int drm_dp_link_probe(struct drm_dp_aux *aux, struct drm_dp_link *link) link->edp = edp_revs[value]; }
+ /* DP_TRAINING_AUX_RD_INTERVAL is in units of 4 milliseconds */ + link->aux_rd_interval = drm_dp_aux_rd_interval(values); + link->rate = link->max_rate; link->lanes = link->max_lanes;
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index 825aaf4e8c71..20ae0e413b64 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -678,6 +678,22 @@ drm_dp_alternate_scrambler_reset_cap(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) DP_ALTERNATE_SCRAMBLER_RESET_CAP; }
+/** + * drm_dp_read_aux_interval() - read the AUX read interval from the DPCD + * @dpcd: receiver capacity buffer + * + * Reads the AUX read interval (in microseconds) from the DPCD. Note that the + * TRAINING_AUX_RD_INTERVAL stores the value in units of 4 milliseconds. + * + * Returns: + * The read AUX interval in microseconds. + */ +static inline unsigned int +drm_dp_aux_rd_interval(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) +{ + return dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4000; +} + /* * DisplayPort AUX channel */ @@ -805,6 +821,7 @@ struct drm_dp_link { unsigned int max_lanes;
struct drm_dp_link_caps caps; + unsigned int aux_rd_interval; unsigned char edp;
unsigned int rate;