[alsa-devel] [PATCH] ASoC: remove a card from the list, if instantiation failed

[Guennadi Liakhovetski]

On Wed, 17 Mar 2010, Mark Brown wrote:

> On 17 Mar 2010, at 21:06, Guennadi Liakhovetski <g.liakhovetski at gmx.de> wrote:
> 
> > If instantiation of a card failed, we have to remove it from the card
> > list. This fixes an Oops on Migo-R, triggering, when after a failed
> > firmware load attempt the driver modules are removed and re-inserted
> > again.
> 
> This looks like the wrong fix - if the card failed to instantiate because the
> component drivers weren't ready then it ought to hang around so it can be
> instantiated once they appear. Presumably some part of the instantiation
> attempt is failing and not being unwound properly?

If snd_soc_instantiate_card() fails, when called from 
snd_soc_register_card(), the card currently stays on the list, but the 
instantiated flag is not set. If you then unload drivers and unregister 
the soc-audio platform device, snd_soc_unregister_card() is called, but 
since instantiated is not set, nothing is done and the card stays on the 
list. What's the proper unwind way in such a case then?

Thanks
Guennadi

> 
> > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski at gmx.de>
> > ---
> > 
> > Should also be good for stable.
> > 
> > diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
> > index c8b0556..307eea0 100644
> > --- a/sound/soc/soc-core.c
> > +++ b/sound/soc/soc-core.c
> > @@ -2361,6 +2361,8 @@ static int snd_soc_register_card(struct snd_soc_card
> > *card)
> >   mutex_lock(&client_mutex);
> >   list_add(&card->list, &card_list);
> >   snd_soc_instantiate_cards();
> > +    if (!card->instantiated)
> > +        list_del(&card->list);
> >   mutex_unlock(&client_mutex);
> > 
> >   dev_dbg(card->dev, "Registered card '%s'\n", card->name);

---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/