Re: USB sound card freezes USB after resume from suspend

[Geraldo Nascimento <geraldogabriel@gmail.com>]

Hello Jakub and Takashi,

On Wed, Apr 26, 2023 at 07:24:50AM +0200, Takashi Iwai wrote:
> On Tue, 25 Apr 2023 20:19:24 +0200,
> Jakub Kicinski wrote:
> > 
> > Hi!
> > 
> > For a few weeks now I can't use any USB devices if I suspend my laptop
> > with my USB sound card active and resuming it without it connected.

Takashi, did you pay attention to the workflow of triggering Jakub's
bug? He suspends the computer with the sound card active, disconnects
the sound card and expects to resume his computer back to an usable
state.

IMHO this is a very believable report and I can see something going
possibly wrong with this workflow. I understand you need the bisection
from Jakub to get a clearer picture, I was just emphasizing the point
that Jakub seems to be disconnecting the USB sound card during suspend
and then resuming, at least that's what I was able to understand.

Thanks,
Geraldo Nascimento

> > 
> > USB worker threads seems to be sitting in:
> > 
> > [<0>] snd_pcm_dev_disconnect+0x1e8/0x280 [snd_pcm]
> > [<0>] snd_device_disconnect_all+0x42/0x80 [snd]
> > [<0>] snd_card_disconnect+0x128/0x290 [snd]
> > [<0>] usb_audio_disconnect+0x11a/0x2c0 [snd_usb_audio]
> > [<0>] usb_unbind_interface+0x8c/0x270
> > [<0>] device_release_driver_internal+0x1b2/0x230
> > [<0>] bus_remove_device+0xd8/0x150
> > [<0>] device_del+0x18b/0x410
> > [<0>] usb_disable_device+0xc6/0x1e0
> > [<0>] usb_disconnect+0xda/0x2c0
> > [<0>] usb_disconnect+0xbf/0x2c0
> > [<0>] usb_disconnect+0xbf/0x2c0
> > [<0>] usb_disconnect+0xbf/0x2c0
> > [<0>] hub_event+0xf01/0x1cd0
> > [<0>] process_one_work+0x1c4/0x3d0
> > [<0>] worker_thread+0x4d/0x380
> > [<0>] kthread+0xe6/0x110
> > [<0>] ret_from_fork+0x29/0x50
> > 
> > Which is:
> > 
> > snd_pcm_dev_disconnect (/usr/src/debug/kernel-6.2.12/linux-6.2.12-300.fc38.x86_64/sound/core/pcm.c:818 /usr/src/debug/kernel-6.2.12/linux-6.2.12-300.fc38.x86_64/sound/core/pcm.c:812 /usr/src/debug/kernel-6.2.12/linux-6.2.12-300.fc38.x86_64/sound/core/pcm.c:1129) snd_pcm
> > 
> > It happens on Fedora 37 and Fedora 38, it seems to have coincided with
> > the 6.2 kernel but I'm not 100% sure.
> > 
> > The USB devices come back after half an hour or so, silently.
> > There's nothing of note in dmesg.
> 
> AFAIK, there has been no similar report, so far.
> 
> Is it a regression?  If yes, could you figure out which kernel version
> starts showing the problem (or at best bisection)?
> 
> 
> thanks,
> 
> Takashi