kernel/linux.git/drivers/gpu/drm/amd/display/dc/link, branch v6.18.22

drm/amd/display: Don't disable DPCD mst_en if sink connected

2026-03-04T12:19:49+00:00

[ Upstream commit 9aeb31b2456452257ad1ff7ec566f21bab1f3e8a ] [WHY] User may connect mst dock with multi monitors and do quick unplug and plug in one of the monitor. This operatioin may create CSN from dock to display driver. Then display driver would disable and then enable mst link and also disable/enable DPCD mst_en bit in dock RX. However, when mst_en bit being disabled, if dock has another CSN message to transmit then the message would be removed because of the disabling of mst_en. In this case, the message is missing and it ends up no display in the replugged monitor. [HOW] Don't disable mst_en bit when link still has sink connected. Reviewed-by: Wenjing Liu Signed-off-by: Peichen Huang Signed-off-by: Chenyu Chen Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amd/display: Correct FIXED_VS Link Rate Toggle Condition

2026-03-04T12:19:47+00:00

[ Upstream commit 531fe6e0fee85a1bdb5b8223a706fff654ed0a61 ] [WHY&HOW] The condition is only perform toggle if FIXED_VS LTTPR reports no IEEE OUI. The literal "\x0,\x0,\x0" contains commas changes the bytes being compared to {0x00,0x2C,0X00}. The correct literal should be "\x00\x00\x00" without commas. Reviewed-by: Charlene Liu Reviewed-by: Wenjing Liu Signed-off-by: Jing Zhou Signed-off-by: Roman Li Tested-by: Dan Wheeler Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin

drm/amd/display: Bump the HDMI clock to 340MHz

2026-01-23T10:21:30+00:00

commit fee50077656d8a58011f13bca48f743d1b6d6015 upstream. [Why] DP-HDMI dongles can execeed bandwidth requirements on high resolution monitors. This can lead to pruning the high resolution modes. HDMI 1.3 bumped the clock to 340MHz, but display code never matched it. [How] Set default to (DVI) 165MHz. Once HDMI display is identified update to 340MHz. Reported-by: Dianne Skoll Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4780 Reviewed-by: Chris Park Signed-off-by: Mario Limonciello Signed-off-by: Matthew Stewart Tested-by: Dan Wheeler Signed-off-by: Alex Deucher (cherry picked from commit ac1e65d8ade46c09fb184579b81acadf36dcb91e) Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman

Revert "drm/amd/display: Move setup_stream_attribute"

2025-11-26T17:16:58+00:00

This reverts commit 2681bf4ae8d24df950138b8c9ea9c271cd62e414. This results in a blank screen on the HDMI port on some systems. Revert for now so as not to regress 6.18, can be addressed in 6.19 once the issue is root caused. Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4652 Cc: Sunpeng.Li@amd.com Cc: ivan.lipski@amd.com Signed-off-by: Alex Deucher (cherry picked from commit d0e9de7a81503cdde37fb2d37f1d102f9e0f38fb)

drm/amd/display: Increase DPCD read retries

2025-11-18T17:06:34+00:00

[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

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

2025-11-18T17:03:42+00:00

[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

drm/amd/display: Fix black screen with HDMI outputs

2025-11-04T18:24:40+00:00

[Why & How] This fixes the black screen issue on certain APUs with HDMI, accompanied by the following messages: amdgpu 0000:c4:00.0: amdgpu: [drm] Failed to setup vendor info frame on connector DP-1: -22 amdgpu 0000:c4:00.0: [drm] Cannot find any crtc or sizes [drm] Cannot find any crtc or sizes Fixes: 489f0f600ce2 ("drm/amd/display: Fix DVI-D/HDMI adapters") Suggested-by: Timur Kristóf Reviewed-by: Harry Wentland Signed-off-by: Alex Hung Signed-off-by: Ray Wu Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher (cherry picked from commit 678c901443a6d2e909e3b51331a20f9d8f84ce82)

drm/amd/display: Fix NULL pointer dereference

2025-10-21T13:45:33+00:00

[Why] On a mst branch with multi display setup, dc context is obselete after updating the first stream. Referencing the same dc context for the next stream update to fetch dc pointer leads to NULL pointer dereference. [How] Get the dc pointer from the link rather than context. Cc: Mario Limonciello Cc: Alex Deucher Reviewed-by: Charlene Liu Signed-off-by: Meenakshikumar Somasundaram Signed-off-by: Aurabindo Pillai Signed-off-by: Alex Deucher (cherry picked from commit dc69b48988b171d6ccb3a083607e4dff015e2c0d) Cc: stable@vger.kernel.org

drm/amd/display: Add monitor patch to read psr cap again

2025-09-23T14:26:47+00:00

[Why & How] According to the vendor’s requirement, after each OUI write, the PSR cap must be read; otherwise, the vendor will default to using PSRSU. But its PSR cap indicates that it only supports PSR1. Reviewed-by: Wenjing Liu Signed-off-by: Paul Hsieh Signed-off-by: Ivan Lipski Tested-by: Dan Wheeler Signed-off-by: Alex Deucher

drm/amd/display: Fix DVI-D/HDMI adapters

2025-09-15T21:03:50+00:00

When the EDID has the HDMI bit, we should simply select the HDMI signal type even on DVI ports. For reference see, the legacy amdgpu display code: amdgpu_atombios_encoder_get_encoder_mode which selects ATOM_ENCODER_MODE_HDMI for the same case. This commit fixes DVI connectors to work with DVI-D/HDMI adapters so that they can now produce output over these connectors for HDMI monitors with higher bandwidth modes. With this change, even HDMI audio works through DVI. For testing, I used a CAA-DMDHFD3 DVI-D/HDMI adapter with the following GPUs: Tahiti (DCE 6) - DC can now output 4K 30 Hz over DVI Polaris 10 (DCE 11.2) - DC can now output 4K 60 Hz over DVI Signed-off-by: Timur Kristóf Acked-by: Alex Deucher Reviewed-by: Alex Hung Signed-off-by: Alex Deucher