kernel/linux.git/drivers/gpu/drm/amd/display/dc/link/protocols, branch v6.6.150

drm/amd/display: Move sleep into each retry for retrieve_link_cap()

2025-12-01T10:41:45+00:00

commit 71ad9054c1f241be63f9d11df8cbd0aa0352fe16 upstream. [Why] When a monitor is booting it's possible that it isn't ready to retrieve link caps and this can lead to an EDID read failure: ``` [drm:retrieve_link_cap [amdgpu]] *ERROR* retrieve_link_cap: Read receiver caps dpcd data failed. amdgpu 0000:c5:00.0: [drm] *ERROR* No EDID read. ``` [How] Rather than msleep once and try a few times, msleep each time. Should be no changes for existing working monitors, but should correct reading caps on a monitor that is slow to boot. Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4672 Reviewed-by: Alex Hung Signed-off-by: Mario Limonciello (AMD) Signed-off-by: Ivan Lipski Tested-by: Dan Wheeler Signed-off-by: Alex Deucher (cherry picked from commit 669dca37b3348a447db04bbdcbb3def94d5997cc) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

drm/amd/display: Increase DPCD read retries

2025-12-01T10:41:45+00:00

commit 8612badc331bcab2068baefa69e1458085ed89e3 upstream. [Why] Empirical measurement of some monitors that fail to read EDID while booting shows that the number of retries with a 30ms delay between tries is as high as 16. [How] Increase number of retries to 20. Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4672 Reviewed-by: Alex Hung Signed-off-by: Mario Limonciello (AMD) Signed-off-by: Ivan Lipski Tested-by: Dan Wheeler Signed-off-by: Alex Deucher (cherry picked from commit ad1c59ad7cf74ec06e32fe2c330ac1e957222288) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

drm/amd/display: Increase AUX Intra-Hop Done Max Wait Duration

2025-11-24T09:29:24+00:00

[ Upstream commit e3419e1e44b87d4176fb98679a77301b1ca40f63 ] [WHY] In the worst case, AUX intra-hop done can take hundreds of milliseconds as each retimer in a link might have to wait a full AUX_RD_INTERVAL to send LT abort downstream. [HOW] Wait 300ms for each retimer in a link to allow time to propagate a LT abort without infinitely waiting on intra-hop done. For no-retimer case, keep the max duration at 10ms. Reviewed-by: Wenjing Liu Signed-off-by: Michael Strauss Signed-off-by: Ivan Lipski Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amd/display: Update CR AUX RD interval interpretation

2025-06-04T12:42:10+00:00

[ Upstream commit 6a7fde433231c18164c117592d3e18ced648ad58 ] [Why] DP spec updated to have the CR AUX RD interval match the EQ AUX RD interval interpretation of DPCD 0000Eh/0220Eh for 8b/10b non-LTTPR mode and LTTPR transparent mode cases. [How] Update interpretation of DPCD 0000Eh/0220Eh for CR AUX RD interval during 8b/10b link training. Reviewed-by: Michael Strauss Reviewed-by: Wenjing Liu Signed-off-by: George Shen Signed-off-by: Zaeem Mohamed Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amd/display: Don't try AUX transactions on disconnected link

2025-06-04T12:42:10+00:00

[ Upstream commit e8bffa52e0253cfd689813a620e64521256bc712 ] [Why] Setting link DPMS off in response to HPD disconnect creates AUX transactions on a link that is supposed to be disconnected. This can cause issues in some cases when the sink re-asserts HPD and expects source to re-enable the link. [How] Avoid AUX transactions on disconnected link. Reviewed-by: Wenjing Liu Signed-off-by: Ilya Bakoulin Signed-off-by: Aurabindo Pillai Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amd/display: Add support for disconnected eDP streams

2025-06-04T12:42:07+00:00

[ Upstream commit 6571bef25fe48c642f7a69ccf7c3198b317c136a ] [Why] eDP may not be connected to the GPU on driver start causing fail enumeration. [How] Move the virtual signal type check before the eDP connector signal check. Reviewed-by: Wenjing Liu Signed-off-by: Harry VanZyllDeJong Signed-off-by: Roman Li Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amd/display: Skip checking FRL_MODE bit for PCON BW determination

2025-06-04T12:42:02+00:00

[ Upstream commit 0584bbcf0c53c133081100e4f4c9fe41e598d045 ] [Why/How] Certain PCON will clear the FRL_MODE bit despite supporting the link BW indicated in the other bits. Thus, skip checking the FRL_MODE bit when interpreting the hdmi_encoded_link_bw struct. Reviewed-by: Wenjing Liu Signed-off-by: George Shen Signed-off-by: Wayne Lin Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amd/display: Fix incorrect DPCD configs while Replay/PSR switch

2025-06-04T12:42:00+00:00

[ Upstream commit 0d9cabc8f591ea1cd97c071b853b75b155c13259 ] [Why] When switching between PSR/Replay, the DPCD config of previous mode is not cleared, resulting in unexpected behavior in TCON. [How] Initialize the DPCD in setup function Reviewed-by: Robin Chen Signed-off-by: Leon Huang Signed-off-by: Tom Chung Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amd/display: add workaround flag to link to force FFE preset

2025-04-25T08:45:17+00:00

[ Upstream commit 51d1b338541dea83fec8e6f95d3e46fa469a73a8 ] [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 Signed-off-by: Sasha Levin

drm/amd/display: Fix FEC_READY write on DP LT

2024-09-18T17:24:07+00:00

[ Upstream commit a8baec4623aedf36d50767627f6eae5ebf07c6fb ] [Why/How] We can miss writing FEC_READY in some cases before LT start, which violates DP spec. Remove the condition guarding the DPCD write so that the write happens unconditionally. Cc: Mario Limonciello Cc: Alex Deucher Cc: stable@vger.kernel.org Reviewed-by: Wenjing Liu Acked-by: Wayne Lin Signed-off-by: Ilya Bakoulin Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin