Re: USB sound card freezes USB after resume from suspend

[Takashi Iwai <tiwai@suse.de>]

On Wed, 26 Apr 2023 07:46:47 +0200,
Geraldo Nascimento wrote:
> 
> 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.

It's a pretty normal procedure for many people; most of USB type-C
docks have a USB audio built-in, and people remove the machine from
the dock after suspend.  So that's an operation that is seen everyday
everywhere.

Still I haven't heard this issue, and it implies that it's either
something new or specific to the machine or the environment.  Or we've
been just lucky...


Takashi

> 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
>