From: Brendan Tam Date: Thu, 23 Jan 2025 16:25:16 +0000 (-0500) Subject: drm/amd/display: add workaround flag to link to force FFE preset X-Git-Tag: v6.15-rc1~120^2~17^2~78 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=51d1b338541dea83fec8e6f95d3e46fa469a73a8;p=thirdparty%2Flinux.git drm/amd/display: add workaround flag to link to force FFE preset [Why] There have been instances of some monitors being unable to link train on their reported link speed using their selected FFE preset. If a different FFE preset is found that has a higher rate of success during link training this workaround can be used to force its FFE preset. [How] A new link workaround flag is made called force_dp_ffe_preset. The flag is checked in override_training_settings and will set lt_settings->ffe_preset which is null if the flag is not set. The flag is then set in override_lane_settings. Reviewed-by: Wenjing Liu Signed-off-by: Brendan Tam Signed-off-by: Aurabindo Pillai Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher --- diff --git a/drivers/gpu/drm/amd/display/dc/dc.h b/drivers/gpu/drm/amd/display/dc/dc.h index e1f4f643c3647..16cd7833e9318 100644 --- a/drivers/gpu/drm/amd/display/dc/dc.h +++ b/drivers/gpu/drm/amd/display/dc/dc.h @@ -1792,7 +1792,9 @@ struct dc_link { bool dongle_mode_timing_override; bool blank_stream_on_ocs_change; bool read_dpcd204h_on_irq_hpd; + bool force_dp_ffe_preset; } wa_flags; + union dc_dp_ffe_preset forced_dp_ffe_preset; struct link_mst_stream_allocation_table mst_stream_alloc_table; struct dc_link_status link_status; diff --git a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c index 88d4288cde0f5..751c18e592ea5 100644 --- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c +++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_training.c @@ -736,6 +736,8 @@ void override_training_settings( lt_settings->pre_emphasis = overrides->pre_emphasis; if (overrides->post_cursor2 != NULL) lt_settings->post_cursor2 = overrides->post_cursor2; + if (link->wa_flags.force_dp_ffe_preset && !dp_is_lttpr_present(link)) + lt_settings->ffe_preset = &link->forced_dp_ffe_preset; if (overrides->ffe_preset != NULL) lt_settings->ffe_preset = overrides->ffe_preset; /* Override HW lane settings with BIOS forced values if present */