From 98025a62cb00778a467dbc359d647c9515d51b4e Mon Sep 17 00:00:00 2001 From: Nikola Cornij Date: Thu, 29 Apr 2021 18:11:51 -0400 Subject: drm/dp_mst: Use Extended Base Receiver Capability DPCD space [why] DP 1.4a spec mandates that if DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT is set, Extended Base Receiver Capability DPCD space must be used. Without doing that, the three DPCD values that differ will be wrong, leading to incorrect or limited functionality. MST link rate, for example, could have a lower value. Also, Synaptics quirk wouldn't work out well when Extended DPCD was not read, resulting in no DSC for such hubs. [how] Modify MST topology manager to use the values from Extended DPCD where applicable. To prevent regression on the sources that have a lower maximum link rate capability than MAX_LINK_RATE from Extended DPCD, have the drivers supply maximum lane count and rate at initialization time. This also reverts commit 2dcab875e763 ("Revert drm/dp_mst: Retrieve extended DPCD caps for topology manager"), brining the change back to the original commit ad44c03208e4 ("drm/dp_mst: Retrieve extended DPCD caps for topology manager"). Signed-off-by: Nikola Cornij Reviewed-by: Lyude Paul Signed-off-by: Lyude Paul Link: https://patchwork.freedesktop.org/patch/msgid/20210429221151.22020-2-nikola.cornij@amd.com --- drivers/gpu/drm/amd/display/dc/dc_link.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/gpu/drm/amd/display/dc/dc_link.h') diff --git a/drivers/gpu/drm/amd/display/dc/dc_link.h b/drivers/gpu/drm/amd/display/dc/dc_link.h index b0013e674864..cb6d0543d839 100644 --- a/drivers/gpu/drm/amd/display/dc/dc_link.h +++ b/drivers/gpu/drm/amd/display/dc/dc_link.h @@ -346,6 +346,8 @@ bool dc_link_dp_set_test_pattern( const unsigned char *p_custom_pattern, unsigned int cust_pattern_size); +bool dc_link_dp_get_max_link_enc_cap(const struct dc_link *link, struct dc_link_settings *max_link_enc_cap); + void dc_link_enable_hpd_filter(struct dc_link *link, bool enable); bool dc_link_is_dp_sink_present(struct dc_link *link); -- cgit v1.2.3