In my system during certain power events the power rail for the TLV320AIC3120 goes away and may come back.
To accommodate this I have added a call to snd_soc_unregister_card as soon as I notice via GPIO that this power has been removed. I then call snd_soc_register_card to re-install the sound card after power is restored.
If no sound is playing when the asynchronous power removal occurs this works fine.
If a sound is playing one of two things will occur. In the first case the sound driver comes back and sound is restored when power is restored. In the second case my deferred work function which calls the snd_soc_unregister_card function gets hung and does not return.
I have traced the difference to the wait_for_completion call in snd_card_free. if snd_card_disconnect adds files to shutdown_files list then wait_for_completion will hang forever.
Any suggestions on how to further debug this?
How to force the immediate unregister of the card even if a sound is playing?
Thank you,
Dexter Travis