[alsa-devel] Question about struct snd_soc_dai() :: cpu_dai->codec

[Takashi Iwai]

On Wed, 27 Jul 2016 05:21:11 +0200,
Vinod Koul wrote:
> 
> On Tue, Jul 26, 2016 at 05:41:56AM +0000, Kuninori Morimoto wrote:
> > 
> > Hi ALSA SoC
> > 
> > My current headache is ALSA SoC's each modules (= Card/Codec/CPU/Platform)
> > doesn't care about "unbind/rmmod".
> > For example, if someone unbinded/rmmoded "Codec", Card or other modules
> > doesn't know about it. Thus, user can continue to use this sound card,
> > and kernel will be Oops.
> 
> Are you sure about this? Have you tried removing a module?
> 
> During card probe, asoc will hold a reference to the component. See the
> calls to try_module_get(). This will prevent from unloading under normal
> cases.

For unloading the module, yes, it should have been prevented by
managing the module refcount.  However, unbinding can't be stopped by
that.  It's a known problem.

Morimoto-san, do you see the issue really via module unloading, or is
it only via unbinding?


Takashi