drm/amd/display: Test dm_dmub_outbox1_low_irq drain and work guards

[WHAT]
Add KUnit tests for dm_dmub_outbox1_low_irq() draining a trace ring up
to the DMUB_TRACE_MAX_READ cap, dm_handle_hpd_work() rejecting a work
item with no notification, and amdgpu_dm_irq_schedule_work() not
queueing once the IRQ workqueue is gone.

[HOW]
Back dmub->outbox0_rb with a fake ring whose write pointer sits one
entry past the cap, and keep the ring larger so the read pointer does
not wrap. dm_handle_hpd_work() returns before its own kfree() on the
NULL-notify path, so the test frees the work item.

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 19:04:17 -06:00 • committed by Alex Deucher
commit 9a678a38d1