USB sound card freezes USB after resume from suspend

USB sound card freezes USB after resume from suspend

[Jakub Kicinski]

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.

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.

Re: USB sound card freezes USB after resume from suspend

[Takashi Iwai]

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.
> 
> 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

Re: USB sound card freezes USB after resume from suspend

[Geraldo Nascimento]

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

Re: USB sound card freezes USB after resume from suspend

[Takashi Iwai]

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
> 

Re: USB sound card freezes USB after resume from suspend

[Geraldo Nascimento]

On Wed, Apr 26, 2023 at 08:02:58AM +0200, Takashi Iwai wrote:
> 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

Understood, sorry for adding noise then.

Thanks,
Geraldo Nascimento

Re: USB sound card freezes USB after resume from suspend

[Jaroslav Kysela]

On 26. 04. 23 7:24, 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.
>>
>> 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)?

It seems that it may be related to free_chmap():

(gdb) l *(snd_pcm_dev_disconnect+0x1e8)
0xef0 is in snd_pcm_dev_disconnect (sound/core/pcm.c:817).
812	static void free_chmap(struct snd_pcm_str *pstr)
813	{
814		if (pstr->chmap_kctl) {
815			struct snd_card *card = pstr->pcm->card;
816	
817			down_write(&card->controls_rwsem);
818			snd_ctl_remove(card, pstr->chmap_kctl);
819			up_write(&card->controls_rwsem);
820			pstr->chmap_kctl = NULL;
821		}

I think that the chmap should be freed only in snd_pcm_free_stream() to avoid 
possible nested mutex locks. This operation does not belong to disconnect.

But I cannot reproduce this lock here.

					Jaroslav

-- 
Jaroslav Kysela <perex@perex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.

Re: USB sound card freezes USB after resume from suspend

[Takashi Iwai]

On Wed, 26 Apr 2023 10:01:11 +0200,
Jaroslav Kysela wrote:
> 
> On 26. 04. 23 7:24, 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.
> >> 
> >> 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)?
> 
> It seems that it may be related to free_chmap():
> 
> (gdb) l *(snd_pcm_dev_disconnect+0x1e8)
> 0xef0 is in snd_pcm_dev_disconnect (sound/core/pcm.c:817).
> 812	static void free_chmap(struct snd_pcm_str *pstr)
> 813	{
> 814		if (pstr->chmap_kctl) {
> 815			struct snd_card *card = pstr->pcm->card;
> 816	
> 817			down_write(&card->controls_rwsem);
> 818			snd_ctl_remove(card, pstr->chmap_kctl);
> 819			up_write(&card->controls_rwsem);
> 820			pstr->chmap_kctl = NULL;
> 821		}
> 
> I think that the chmap should be freed only in snd_pcm_free_stream()
> to avoid possible nested mutex locks. This operation does not belong
> to disconnect.

A good point, it'll be a patch like below.
But we still need to figure out what's actually happening there.
 
> But I cannot reproduce this lock here.

Here too.  Could be tied with the config or the device?


thanks,

Takashi

-- 8< --
--- a/sound/core/pcm.c
+++ b/sound/core/pcm.c
@@ -1126,7 +1126,6 @@ static int snd_pcm_dev_disconnect(struct snd_device *device)
 	pcm_call_notify(pcm, n_disconnect);
 	for (cidx = 0; cidx < 2; cidx++) {
 		snd_unregister_device(&pcm->streams[cidx].dev);
-		free_chmap(&pcm->streams[cidx]);
 	}
 	mutex_unlock(&pcm->open_mutex);
 	mutex_unlock(&register_mutex);

Re: USB sound card freezes USB after resume from suspend

[Jaroslav Kysela]

On 26. 04. 23 10:14, Takashi Iwai wrote:
> On Wed, 26 Apr 2023 10:01:11 +0200,
> Jaroslav Kysela wrote:
>>
>> On 26. 04. 23 7:24, 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.
>>>>
>>>> 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)?
>>
>> It seems that it may be related to free_chmap():
>>
>> (gdb) l *(snd_pcm_dev_disconnect+0x1e8)
>> 0xef0 is in snd_pcm_dev_disconnect (sound/core/pcm.c:817).
>> 812	static void free_chmap(struct snd_pcm_str *pstr)
>> 813	{
>> 814		if (pstr->chmap_kctl) {
>> 815			struct snd_card *card = pstr->pcm->card;
>> 816	
>> 817			down_write(&card->controls_rwsem);
>> 818			snd_ctl_remove(card, pstr->chmap_kctl);
>> 819			up_write(&card->controls_rwsem);
>> 820			pstr->chmap_kctl = NULL;
>> 821		}
>>
>> I think that the chmap should be freed only in snd_pcm_free_stream()
>> to avoid possible nested mutex locks. This operation does not belong
>> to disconnect.
> 
> A good point, it'll be a patch like below.

It looks good.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>

> But we still need to figure out what's actually happening there.
>   
>> But I cannot reproduce this lock here.
> 
> Here too.  Could be tied with the config or the device?

Perhaps. Jakub, could you do more debugging (printk, traces)?

					Jaroslav

-- 
Jaroslav Kysela <perex@perex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.

Re: USB sound card freezes USB after resume from suspend

[Jakub Kicinski]

On Wed, 26 Apr 2023 13:04:15 +0200 Jaroslav Kysela wrote:
> > A good point, it'll be a patch like below.  
> 
> It looks good.
> 
> Reviewed-by: Jaroslav Kysela <perex@perex.cz>
> 
> > But we still need to figure out what's actually happening there.
> >     
> >> But I cannot reproduce this lock here.  
> > 
> > Here too.  Could be tied with the config or the device?  
> 
> Perhaps. Jakub, could you do more debugging (printk, traces)?

Let me get back to you on Saturday - I'll test the patch and try a bit
of bisecting. Can't promise much in terms of printing, because IDK what
to print :(