Re: [PATCH v6] drm/bridge: dw-hdmi-qp: serialize HDMI audio callbacks with PHY enable/disable

[Frank Zhang]

On 9/17/26 00:09, Igor Paunovic wrote:
> Hi Frank,
>
> I tested v6 on an Orange Pi 5 Plus (RK3588): git am onto a
> drm-misc-next based 7.3.0-rc2 tree with PROVE_LOCKING and
> DEBUG_ATOMIC_SLEEP, HDMI output to a TV.
>
> The reproducer I used on v5 (output off, then open and close the PCM)
> now stops at the open: dw_hdmi_qp_audio_enable() returned -EOPNOTSUPP
> three times out of three, nothing from ASoC or the bridge was logged,
> and since the startup failed, the shutdown path never reached
> clear_audio_infoframe().
>
> So I also ran the sequence from your commit message: PCM opened with
> the output on, output turned off by the compositor while the stream
> runs, PCM closed after that. With function_graph on
> dw_hdmi_qp_bridge_clear_audio_infoframe() and
> dw_hdmi_qp_audio_enable(), the clear call after the disable takes and
> drops phy.lock and returns 0 with no regmap access inside it; with the
> output on, as a control, one regmap_update_bits_base() call shows up
> inside it, under the lock.
>
> There was no external abort, SError, lockdep report or might_sleep
> splat in the whole run, including two output off/on cycles, and once
> the output was back on a new stream played on the TV.
>
> Tested-by: Igor Paunovic <royalnet026@xxxxxxxxx> # Orange Pi 5 Plus (RK3588)
>
> Not covered: I did not try to hit the window the lock is meant to
> close (an atomic disable landing between the state check and a
> register write), so that part rests on the code; and I did not check
> Dmitry's condition from v2 [1] that a PHY off/on cycle clears the
> audio registers.
>
> v6 overlaps with Detlev's patch [2] (both return -EOPNOTSUPP from the
> audio callbacks while the output is off), and [2] no longer applies on
> top of v6. For the crash, v6 alone now covers both sequences from my
> v5 note (open with the output already off, and the output going away
> under an open PCM), so my remark there that both patches are needed
> does not apply to v6.
>
> An LLM assistant applied and built the patch, wrote the test scripts,
> counted the traces and helped draft this mail; I ran the tests on the
> board and did the listening myself.
>
> [1] https://lore.kernel.org/all/urguajogb4zsz4jg3ef32hpyf2awxkywdtlk5ackdi2gjai4l7@vpjaf3sznkto/
> [2] https://lore.kernel.org/all/20260519-fix-hdmi-audio-warnings-v1-1-9608966c993f@xxxxxxxxxxxxx/
>
> Igor

Hi Igor,

Thanks for your testing.

Best regards,
Frank