drm/amd/display: Block UHBR Based On USB-C PD Cable ID

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[WHY]
Currently the absence of UHBR cable ID caps from USB-C PD does not block UHBR
rates. In situations where DPCD reports valid UHBR capability but USB-C PD
does not, such as using a USB-C to DP1.4 dongle connected to a native DP2.1
cable, link loss and lightup failures can be seen as a result.

Additionally, in edge cases where a platform supports cable ID but DMUB
doesn't correctly return cable ID caps, driver currently also allows UHBR.

[HOW]
Block UHBR rates over DP alt mode if cable id indicates no UHBR support.
Additionally, block UHBR rates if a cable ID supported platform receives no
reply from a DMUB cable id query.

Reviewed-by: Wenjing Liu <wenjing.liu@amd.com>
Reviewed-by: Ovidiu Bunea <ovidiu.bunea@amd.com>
Signed-off-by: Michael Strauss <michael.strauss@amd.com>
Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

...

This commit is contained in:

Michael Strauss 2024-09-03 16:23:11 -04:00 • committed by Alex Deucher

parent 0e719a40bf

commit 4f01a68751

1 changed files with 16 additions and 6 deletions

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drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c

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