[alsa-devel] [PATCH v2] Scarlett mixer interface inclusion

[Takashi Iwai]

At Wed, 22 Oct 2014 08:36:50 +0200,
Takashi Iwai wrote:
> 
> > 2) When unloading a device there are numerous sysfs_remove_group issues:
> > usb 1-1.1: USB disconnect, device number 6
> > ------------[ cut here ]------------
> > WARNING: CPU: 0 PID: 54 at /build/buildd/linux-3.16.0/fs/sysfs/group.c:219 sysfs_remove_group+0x99/0xa0()
> > sysfs group ffffffff82cbd6e0 not found for kobject 'midi1'
> (snip)
> > However this issue occured even without the patch applied.
> 
> Yes, there was a similar report, but we couldn't reproduce here.
> It's a Oops coming from OSS midi device.  This is fairly harmless, but
> annoying.  Could you give your kernel config?  Maybe there's some
> difference.

I'm now checking this issue again, and I still couldn't reproduce it
on my local machines.  Could you give your kernel config if this still
happens?

Also, as a blind shot: does the patch below give any difference?


thanks,

Takashi

---
diff --git a/sound/usb/card.c b/sound/usb/card.c
index 69725d5fa2d6..475961afc886 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -595,13 +595,13 @@ static void usb_audio_disconnect(struct usb_interface *intf)
 	up_write(&chip->shutdown_rwsem);
 
 	mutex_lock(&register_mutex);
+	snd_card_disconnect(card);
 	chip->num_interfaces--;
 	if (chip->num_interfaces <= 0) {
 		struct snd_usb_stream *as;
 		struct snd_usb_endpoint *ep;
 		struct usb_mixer_interface *mixer;
 
-		snd_card_disconnect(card);
 		/* release the pcm resources */
 		list_for_each_entry(as, &chip->pcm_list, list) {
 			snd_usb_stream_disconnect(as);