Re: [PATCH] ALSA: hda: Reject codec reset on ASoC (ext_ops) buses

[Takashi Iwai <tiwai@suse.de>]

On Tue, 27 Oct 2026 08:28:35 +0100,
Peter Ujfalusi wrote:
> 
> Writing to the reconfig or clear sysfs nodes of a codec handled by ASoC
> (SOF via hdac_hda, AVS via codecs/hda) hangs the writer.
> 
> snd_hda_codec_reset() sets card->shutdown and calls
> device_release_driver(). With ext_ops the driver unbind unregisters the
> ASoC component, which unbinds and frees the whole ASoC card:
> - snd_card_disconnect() returns early as card->shutdown is already set,
>   so the card's child devices are not removed and snd_card_free() waits
>   for the card release forever.
> - Even without that, freeing the card removes the codec's hwdep device,
>   which owns the sysfs node the reset was issued from, deadlocking in
>   kernfs while waiting for the active write to finish.
> 
> The legacy HDA driver keeps the card across a driver rebind, ASoC does
> not, so the reset cannot be supported there. Return -EOPNOTSUPP and skip
> the misleading "codec is being used" messages in the callers.
> 
> Fixes: 6bae5ea94989 ("ASoC: hdac_hda: add asoc extension for legacy HDA codec drivers")
> Cc: stable@vger.kernel.org
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=222182
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>

Applied now.  Thanks.


Takashi