drm/amd/display: Fix stale replay_events after mod_power stream removal

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[Why]
mod_power_remove_stream() shifts the remaining power_entity slots down
but does not move replay_events, and mod_power_add_stream() does not
initialize it. replay_events therefore stay bound to the map slot
instead of the stream.

When several streams are disabled in one atomic commit,
amdgpu_dm_mod_power_update_streams() removes them one after another.
The eDP stream can then be looked up in a slot whose stale
replay_events already have replay_event_hw_programming set, so
amdgpu_dm_replay_set_event() returns early ("already in desired state")
without calling mod_power_set_replay_event(). Replay is not disabled
before the eDP panel is powered off. After DPMS on, the sink reports
neither replay state nor frame lock (DPCD 0x378 = 0x00, no error bits),
so the HPD IRQ recovery does not trigger and the panel stays black
until a full modeset.

Seen with an eDP panel using FreeSync Replay plus two DP-MST displays:
DPMS off/on of all outputs leaves eDP black, while DPMS of eDP alone
works. Doing an eDP-only DPMS first makes the next all-output DPMS
fail reliably.

[How]
Shift replay_events together with the PSR cached fields in
mod_power_remove_stream() and initialize it to replay_event_vsync in
mod_power_add_stream(), matching the psr_event_vsync initial value used
for PSR (both vsync events are driven together by
amdgpu_dm_crtc_set_static_screen_optimze()).

Tested on 7.3.0-rc3 (238650ef6c): the reproducer above now recovers
reliably, and Replay still engages when the screen is idle.

The issue was debugged with help from an AI assistant (Claude), which
analysed ftrace/kprobe traces and the driver source, pointed to the
missing replay_events handling and suggested this change. I collected
the traces and built and tested the fix on the affected hardware.

Fixes: 4cef2ac4c7 ("drm/amd/display: Introduce power module on Linux")
Assisted-by: Claude:claude-opus-5
Signed-off-by: Simon Polack <spolack+git@mailbox.org>
Reviewed-by: Ray Wu <ray.wu@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

...

This commit is contained in:

Simon Polack 2026-09-17 12:42:34 +02:00 • committed by Alex Deucher

parent a387d5d707

commit 3d47e38e27

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drivers/gpu/drm/amd/display/modules/power/power.c

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