[Intel-gfx] [PATCH 3/3] drm/i915/dp: use new link training delay helpers

Jani Nikula
2021-10-14T15:01:24Z

Use the new link training delay helpers, fixing the delays for
128b/132b.

For existing 8b/10b functionality, this will cause additional 1-byte
DPCD reads for LTTPR delays instead of using the cached values. It's
just too complicated to combine generic helpers with local caching in a
sensible way.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
.../drm/i915/display/intel_dp_link_training.c | 38 +++++++------------
1 file changed, 13 insertions(+), 25 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
index 85676c953e0a..a72f2dc93718 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -683,15 +683,6 @@ intel_dp_prepare_link_train(struct intel_dp *intel_dp,
return true;
}

-static void intel_dp_link_training_clock_recovery_delay(struct intel_dp *intel_dp,
- enum drm_dp_phy dp_phy)
-{
- if (dp_phy == DP_PHY_DPRX)
- drm_dp_link_train_clock_recovery_delay(&intel_dp->aux, intel_dp->dpcd);
- else
- drm_dp_lttpr_link_train_clock_recovery_delay();
-}
-
static bool intel_dp_adjust_request_changed(const struct intel_crtc_state *crtc_state,
const u8 old_link_status[DP_LINK_STATUS_SIZE],
const u8 new_link_status[DP_LINK_STATUS_SIZE])
@@ -750,6 +741,11 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp,
u8 link_status[DP_LINK_STATUS_SIZE];
bool max_vswing_reached = false;
char phy_name[10];
+ int delay_us;
+
+ delay_us = drm_dp_read_clock_recovery_delay(&intel_dp->aux,
+ intel_dp->dpcd, dp_phy,
+ intel_dp_is_uhbr(crtc_state));

intel_dp_phy_name(dp_phy, phy_name, sizeof(phy_name));

@@ -777,7 +773,7 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp,

voltage_tries = 1;
for (cr_tries = 0; cr_tries < max_cr_tries; ++cr_tries) {
- intel_dp_link_training_clock_recovery_delay(intel_dp, dp_phy);
+ usleep_range(delay_us, 2 * delay_us);

if (drm_dp_dpcd_read_phy_link_status(&intel_dp->aux, dp_phy,
link_status) < 0) {
@@ -895,19 +891,6 @@ static u32 intel_dp_training_pattern(struct intel_dp *intel_dp,
return DP_TRAINING_PATTERN_2;
}

-static void
-intel_dp_link_training_channel_equalization_delay(struct intel_dp *intel_dp,
- enum drm_dp_phy dp_phy)
-{
- if (dp_phy == DP_PHY_DPRX) {
- drm_dp_link_train_channel_eq_delay(&intel_dp->aux, intel_dp->dpcd);
- } else {
- const u8 *phy_caps = intel_dp_lttpr_phy_caps(intel_dp, dp_phy);
-
- drm_dp_lttpr_link_train_channel_eq_delay(&intel_dp->aux, phy_caps);
- }
-}
-
/*
* Perform the link training channel equalization phase on the given DP PHY
* using one of training pattern 2, 3 or 4 depending on the source and
@@ -925,6 +908,11 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp,
u8 link_status[DP_LINK_STATUS_SIZE];
bool channel_eq = false;
char phy_name[10];
+ int delay_us;
+
+ delay_us = drm_dp_read_channel_eq_delay(&intel_dp->aux,
+ intel_dp->dpcd, dp_phy,
+ intel_dp_is_uhbr(crtc_state));

intel_dp_phy_name(dp_phy, phy_name, sizeof(phy_name));

@@ -944,8 +932,8 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp,
}

for (tries = 0; tries < 5; tries++) {
- intel_dp_link_training_channel_equalization_delay(intel_dp,
- dp_phy);
+ usleep_range(delay_us, 2 * delay_us);
+
if (drm_dp_dpcd_read_phy_link_status(&intel_dp->aux, dp_phy,
link_status) < 0) {
drm_err(&i915->drm,
--
2.30.2