Source needs to write DPCD 103-106 after receiving a PHY request to change swing/pre-emphasis after reading DPCD 206-207. This is especially needed if there is a retimer between source and sink and the retimer implements AUX_CH interception scheme to manage DP PHY settings (e.g. adjusting Swing/Pre-emphasis equalization level) for DP output channel . If the source doesn't write to DPCD 103-106, the retimer may not output the requested swing/pre-emphasis and eventually we fail compliance.
Signed-off-by: Khaled Almahallawy <[email protected]> --- drivers/gpu/drm/i915/display/intel_dp.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 79c27f91f42c..5044201ca742 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -5503,6 +5503,9 @@ void intel_dp_process_phy_request(struct intel_dp *intel_dp) intel_dp_autotest_phy_ddi_enable(intel_dp, data->num_lanes); + drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_LANE0_SET, + intel_dp->train_set, intel_dp->lane_count); + drm_dp_set_phy_test_pattern(&intel_dp->aux, data, link_status[DP_DPCD_REV]); } -- 2.17.1 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
