[PATCH 1/9] ALSA: hda: Do not unset preset when cleaning up codec

[Cezary Rojewski]

On 2022-07-12 12:46 PM, Takashi Iwai wrote:
> On Tue, 12 Jul 2022 11:42:56 +0200,
> Cezary Rojewski wrote:

...

>> snd_hda_codec_cleanup_for_unbind() is called in more places than just
>> HDAudio codec driver's probe() and remove(). It's also called whenever
>> HDAudio codec soc-component is being removed. Relevant part of the
>> stack showing when does the cleanup function get called during rmmod:
>>
>> [  220.549349]  snd_hda_codec_cleanup_for_unbind+0x25/0x451 [snd_hda_codec]
>> [  220.549536]  ? dump_stack_lvl+0x45/0x49
>> [  220.549568]  hda_codec_remove.cold+0x14/0x138 [snd_soc_hda_codec]
>> [  220.549609]  snd_soc_component_remove+0x34/0x40 [snd_soc_core]
>> [  220.549942]  soc_remove_component+0x113/0x120 [snd_soc_core]
>> [  220.550249]  soc_cleanup_card_resources+0x1a7/0x4a0 [snd_soc_core]
>> [  220.550561]  snd_soc_unbind_card+0x9e/0x190 [snd_soc_core]
>> [  220.550885]  snd_soc_unregister_card+0x28/0x80 [snd_soc_core]
>> [  220.551193]  devm_card_release+0x1d/0x20 [snd_soc_core]
>> [  220.551527]  release_nodes+0x73/0x170
>> [  220.551549]  ? preempt_count_sub+0x18/0xc0
>> [  220.551576]  devres_release_all+0x10a/0x150
>> [  220.551600]  ? devres_remove_group+0x260/0x260
>> [  220.551630]  device_unbind_cleanup+0x14/0xd0
>> [  220.551656]  device_release_driver_internal+0x146/0x1d0
>> [  220.551688]  driver_detach+0x81/0xf0
>> [  220.551716]  bus_remove_driver+0xae/0x170
>> [  220.551743]  driver_unregister+0x4d/0x70
>> [  220.551770]  platform_driver_unregister+0x12/0x20
>> [  220.551799]  avs_hdaudio_driver_exit+0x10/0x12 [snd_soc_avs_hdaudio]
> 
> So, IMO,  you're scratching a wrong surface.  The problem is rather
> that snd_hda_codec_cleanup_for_unbind() is called even if it's not for
> unbinding the codec.


This is how ASoC HDAudio codec component was behaving for years, see 
sound/soc/codecs/hdac_hda.c. If the intention is _not_ do call 
snd_hda_codec_cleanup_for_unbind() then the teardown procedure will 
probably need a little update. Actually.. I'm afraid the init one would 
need an update to. Given how the implementation of HDAudio codec 
component's probe() and remove() looks like, there is no dropping the 
cleanup function without changing the upward path accordingly.

Well, to be honest the init/free procedures of HDAudio codec are a 
little hairy, perhaps it's time to address this.


Regards,
Czarek