drm/amd/display: Test MST sideband message ack path

Browse source

[WHAT]
Add KUnit tests for dm_handle_mst_sideband_msg_ready_event() covering the
DOWN_REP ready bit that is acknowledged at DPCD and re-polled until the
iteration limit, and the case where the acknowledge write keeps failing
and the handler gives up after the third retry.

[HOW]
A live topology manager is needed for the handler to reach its ack path,
so the tests initialise one on a DRM device and arm the DOWN_REP ready
bit in the fake DPCD. The fake AUX channel gains a separate write result
so the ESI read still succeeds while the acknowledge write fails.

Assisted-by: Copilot:Claude-Opus-5
Reviewed-by: Bhawanpreet Lakha <bhawanpreet.lakha@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Ivan Lipski <ivan.lipski@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

...

This commit is contained in:

Alex Hung 2026-08-12 12:47:30 -06:00 • committed by Alex Deucher

parent 11a3136bf6

commit 9b2dac15d2

1 changed files with 80 additions and 0 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

80

drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_mst_types_test.c

View file