snd_card_free_in_thread —
call snd_card_free in thread
int snd_card_free_in_thread (struct snd_card * card);
This function schedules the call of snd_card_free function in a
work queue. When all devices are released (non-busy), the work
is woken up and calls snd_card_free.
When a card can be disconnected at any time by hotplug service,
this function should be used in disconnect (or detach) callback
instead of calling snd_card_free directly.
Returns - zero otherwise a negative error code if the start of thread failed.