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

[Mark Brown]

On 17 Mar 2010, at 23:09, Guennadi Liakhovetski  
<g.liakhovetski at gmx.de> wrote:

> 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?

The card should be removed on unregistration either way.

>
> 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/