drm/amd/display: Block UHBR Based On USB-C PD Cable ID
authorMichael Strauss <michael.strauss@amd.com>
Tue, 3 Sep 2024 20:23:11 +0000 (16:23 -0400)
committerAlex Deucher <alexander.deucher@amd.com>
Tue, 1 Oct 2024 21:31:39 +0000 (17:31 -0400)
commit4f01a68751194d05280d659a65758c09e4af04d6
treebd8f3782bf9ec3f5fd2024b921d723d6e2d41d05
parent0e719a40bf5234e66bbd0f1537e30709ab112b5f
drm/amd/display: Block UHBR Based On USB-C PD Cable ID

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