2007-12-23 22:55:25

by Victor Hahn

[permalink] [raw]
Subject: Can't disconnect a USB sound device and connect another

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

... because it causes lsusb to freeze and gives me this in /var/log/messages:

Dec 23 23:27:04 cabrio kernel: usb 2-2: USB disconnect, address 5
Dec 23 23:27:04 cabrio kernel: PGD 110f2067 PUD 110f3067 PMD 0
Dec 23 23:27:04 cabrio kernel: CPU 0
Dec 23 23:27:04 cabrio kernel: Modules linked in: videodev v4l2_common
v4l1_compat snd_rtctimer binfmt_misc rfcomm l2cap bluetooth capability
commoncap ppdev powernow_k8 cpufreq_userspace cpufreq_stats cpufreq_powersave
cpufreq_ondemand freq_table cpufreq_conservative video output sbs container
dock ac battery ext3 jbd mbcache aes_x86_64 ipv6 it87 hwmon_vid parport_pc lp
parport loop snd_mpu401 snd_mpu401_uart snd_usb_audio snd_pcm_oss
snd_mixer_oss snd_pcm snd_seq_dummy snd_page_alloc snd_usb_lib snd_hwdep
snd_seq_oss analog gameport snd_seq_midi snd_rawmidi snd_seq_midi_event
snd_seq snd_timer snd_seq_device snd psmouse button soundcore serio_raw
i2c_nforce2 k8temp i2c_core pcspkr af_packet shpchp pci_hotplug evdev xfs
sha256 twofish_x86_64 twofish_common cbc blkcipher sg ide_cd cdrom sd_mod
usbhid hid sata_nv 8139too floppy ata_generic 8139cp mii libata scsi_mod
amd74xx ide_core forcedeth ehci_hcd ohci_hcd usbcore dm_crypt dm_mirror
dm_snapshot dm_mod thermal processor fan fuse
Dec 23 23:27:04 cabrio kernel: Pid: 2052, comm: khubd Not tainted 2.6.23.11 #1
Dec 23 23:27:04 cabrio kernel: RIP: 0010:[_end+130488219/2130651808]
[_end+130488219/2130651808] :snd:snd_ctl_dev_disconnect+0x6b/0xb0
Dec 23 23:27:04 cabrio kernel: RSP: 0018:ffff810037bfdc40 EFLAGS: 00010282
Dec 23 23:27:04 cabrio kernel: RAX: 0000000000000000 RBX: 0000000000100100
RCX: 0000000000000018
Dec 23 23:27:04 cabrio kernel: RDX: 0000000000020004 RSI: 000000000000001d
RDI: ffff810013e98c08
Dec 23 23:27:04 cabrio kernel: RBP: ffff8100394631a8 R08: ffff810037bfc000
R09: 0000000000000000
Dec 23 23:27:04 cabrio kernel: R10: 0000000000000000 R11: ffffffff88281910
R12: ffff810039463000
Dec 23 23:27:04 cabrio kernel: R13: ffff810039463168 R14: 0000000000000000
R15: ffff810039463000
Dec 23 23:27:04 cabrio kernel: FS: 00002b24912551e0(0000) GS:ffffffff80533000
(0000) knlGS:00000000f74b16c0
Dec 23 23:27:04 cabrio kernel: CS: 0010 DS: 0018 ES: 0018 CR0:
000000008005003b
Dec 23 23:27:04 cabrio kernel: CR2: 0000000000100100 CR3: 00000000110f1000
CR4: 00000000000006e0
Dec 23 23:27:04 cabrio kernel: DR0: 0000000000000000 DR1: 0000000000000000
DR2: 0000000000000000
Dec 23 23:27:04 cabrio kernel: DR3: 0000000000000000 DR6: 00000000ffff0ff0
DR7: 0000000000000400
Dec 23 23:27:04 cabrio kernel: Process khubd (pid: 2052, threadinfo
ffff810037bfc000, task ffff81003d67d0c0)
Dec 23 23:27:04 cabrio kernel: Stack: 0000000000000000 ffff810038850d00
ffff810039463000 ffff810039463150
Dec 23 23:27:04 cabrio kernel: 0000000000000000 ffffffff88281e69
ffff810038850d00 ffffffff882821ac
Dec 23 23:27:04 cabrio kernel: 0000000000000000 0000000000000000
ffff810039463000 ffff8100394631e0
Dec 23 23:27:04 cabrio kernel: Call Trace:
Dec 23 23:27:04 cabrio kernel:
[_end+130500873/2130651808] :snd:snd_device_disconnect+0x59/0x90
Dec 23 23:27:04 cabrio kernel:
[_end+130501708/2130651808] :snd:snd_device_disconnect_all+0x3c/0x70
Dec 23 23:27:04 cabrio kernel:
[_end+130481675/2130651808] :snd:snd_card_disconnect+0x15b/0x1a0
Dec 23 23:27:04 cabrio kernel:
[_end+131093678/2130651808] :snd_usb_audio:usb_audio_disconnect+0xae/0x1a0
Dec 23 23:27:04 cabrio kernel:
[_end+128211869/2130651808] :usbcore:usb_unbind_interface+0x6d/0xe0
Dec 23 23:27:04 cabrio kernel: [__device_release_driver+130/192]
__device_release_driver+0x82/0xc0
Dec 23 23:27:04 cabrio kernel: [device_release_driver+51/96]
device_release_driver+0x33/0x60
Dec 23 23:27:04 cabrio kernel: [bus_remove_device+118/176]
bus_remove_device+0x76/0xb0
Dec 23 23:27:04 cabrio kernel: [device_del+417/736] device_del+0x1a1/0x2e0
Dec 23 23:27:04 cabrio kernel:
[_end+128198657/2130651808] :usbcore:usb_disable_device+0x91/0x110
Dec 23 23:27:04 cabrio kernel:
[_end+128179466/2130651808] :usbcore:usb_disconnect+0xaa/0x150
Dec 23 23:27:04 cabrio kernel:
[_end+128181649/2130651808] :usbcore:hub_thread+0x401/0xe30
Dec 23 23:27:04 cabrio kernel: [thread_return+87/1463]
thread_return+0x57/0x5b7
Dec 23 23:27:04 cabrio kernel: [autoremove_wake_function+0/48]
autoremove_wake_function+0x0/0x30
Dec 23 23:27:04 cabrio kernel:
[_end+128180624/2130651808] :usbcore:hub_thread+0x0/0xe30
Dec 23 23:27:04 cabrio kernel: [kthread+75/128] kthread+0x4b/0x80
Dec 23 23:27:04 cabrio kernel: [child_rip+10/18] child_rip+0xa/0x12
Dec 23 23:27:04 cabrio kernel: [kthread+0/128] kthread+0x0/0x80
Dec 23 23:27:04 cabrio kernel: [child_rip+0/18] child_rip+0x0/0x12
Dec 23 23:27:04 cabrio kernel:
Dec 23 23:27:04 cabrio kernel:
Dec 23 23:27:04 cabrio kernel: Code: 48 8b 03 0f 18 08 48 39 eb 75 ca 4c 89 ef
e8 d2 35 fd f7 ba
Dec 23 23:27:04 cabrio kernel: RSP <ffff810037bfdc40>

Is there a way to exchange USB audio devices without rebooting?

Beste regards,
Victor
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.6 (GNU/Linux)

iD8DBQFHbuLhX/S6KpIOqB0RAqbsAJ9IGmNHrIX1uqJqhgtIJDO4tcNzGgCfeZgp
G+dpTDupwAQRyV76nm3/qC4=
=Es5+
-----END PGP SIGNATURE-----


2007-12-25 22:05:58

by Andrew Morton

[permalink] [raw]
Subject: Re: Can't disconnect a USB sound device and connect another

On Sun, 23 Dec 2007 23:36:11 +0100 Victor Hahn <[email protected]> wrote:

> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> ... because it causes lsusb to freeze and gives me this in /var/log/messages:

Has this always happened, or is it something we introduced in a recent
kernel?

> Dec 23 23:27:04 cabrio kernel: usb 2-2: USB disconnect, address 5
> Dec 23 23:27:04 cabrio kernel: PGD 110f2067 PUD 110f3067 PMD 0
> Dec 23 23:27:04 cabrio kernel: CPU 0
> Dec 23 23:27:04 cabrio kernel: Modules linked in: videodev v4l2_common
> v4l1_compat snd_rtctimer binfmt_misc rfcomm l2cap bluetooth capability
> commoncap ppdev powernow_k8 cpufreq_userspace cpufreq_stats cpufreq_powersave
> cpufreq_ondemand freq_table cpufreq_conservative video output sbs container
> dock ac battery ext3 jbd mbcache aes_x86_64 ipv6 it87 hwmon_vid parport_pc lp
> parport loop snd_mpu401 snd_mpu401_uart snd_usb_audio snd_pcm_oss
> snd_mixer_oss snd_pcm snd_seq_dummy snd_page_alloc snd_usb_lib snd_hwdep
> snd_seq_oss analog gameport snd_seq_midi snd_rawmidi snd_seq_midi_event
> snd_seq snd_timer snd_seq_device snd psmouse button soundcore serio_raw
> i2c_nforce2 k8temp i2c_core pcspkr af_packet shpchp pci_hotplug evdev xfs
> sha256 twofish_x86_64 twofish_common cbc blkcipher sg ide_cd cdrom sd_mod
> usbhid hid sata_nv 8139too floppy ata_generic 8139cp mii libata scsi_mod
> amd74xx ide_core forcedeth ehci_hcd ohci_hcd usbcore dm_crypt dm_mirror
> dm_snapshot dm_mod thermal processor fan fuse
> Dec 23 23:27:04 cabrio kernel: Pid: 2052, comm: khubd Not tainted 2.6.23.11 #1
> Dec 23 23:27:04 cabrio kernel: RIP: 0010:[_end+130488219/2130651808]
> [_end+130488219/2130651808] :snd:snd_ctl_dev_disconnect+0x6b/0xb0
> Dec 23 23:27:04 cabrio kernel: RSP: 0018:ffff810037bfdc40 EFLAGS: 00010282
> Dec 23 23:27:04 cabrio kernel: RAX: 0000000000000000 RBX: 0000000000100100
> RCX: 0000000000000018
> Dec 23 23:27:04 cabrio kernel: RDX: 0000000000020004 RSI: 000000000000001d
> RDI: ffff810013e98c08
> Dec 23 23:27:04 cabrio kernel: RBP: ffff8100394631a8 R08: ffff810037bfc000
> R09: 0000000000000000
> Dec 23 23:27:04 cabrio kernel: R10: 0000000000000000 R11: ffffffff88281910
> R12: ffff810039463000
> Dec 23 23:27:04 cabrio kernel: R13: ffff810039463168 R14: 0000000000000000
> R15: ffff810039463000
> Dec 23 23:27:04 cabrio kernel: FS: 00002b24912551e0(0000) GS:ffffffff80533000
> (0000) knlGS:00000000f74b16c0
> Dec 23 23:27:04 cabrio kernel: CS: 0010 DS: 0018 ES: 0018 CR0:
> 000000008005003b
> Dec 23 23:27:04 cabrio kernel: CR2: 0000000000100100 CR3: 00000000110f1000
> CR4: 00000000000006e0
> Dec 23 23:27:04 cabrio kernel: DR0: 0000000000000000 DR1: 0000000000000000
> DR2: 0000000000000000
> Dec 23 23:27:04 cabrio kernel: DR3: 0000000000000000 DR6: 00000000ffff0ff0
> DR7: 0000000000000400
> Dec 23 23:27:04 cabrio kernel: Process khubd (pid: 2052, threadinfo
> ffff810037bfc000, task ffff81003d67d0c0)
> Dec 23 23:27:04 cabrio kernel: Stack: 0000000000000000 ffff810038850d00
> ffff810039463000 ffff810039463150
> Dec 23 23:27:04 cabrio kernel: 0000000000000000 ffffffff88281e69
> ffff810038850d00 ffffffff882821ac
> Dec 23 23:27:04 cabrio kernel: 0000000000000000 0000000000000000
> ffff810039463000 ffff8100394631e0
> Dec 23 23:27:04 cabrio kernel: Call Trace:
> Dec 23 23:27:04 cabrio kernel:
> [_end+130500873/2130651808] :snd:snd_device_disconnect+0x59/0x90
> Dec 23 23:27:04 cabrio kernel:
> [_end+130501708/2130651808] :snd:snd_device_disconnect_all+0x3c/0x70
> Dec 23 23:27:04 cabrio kernel:
> [_end+130481675/2130651808] :snd:snd_card_disconnect+0x15b/0x1a0
> Dec 23 23:27:04 cabrio kernel:
> [_end+131093678/2130651808] :snd_usb_audio:usb_audio_disconnect+0xae/0x1a0
> Dec 23 23:27:04 cabrio kernel:
> [_end+128211869/2130651808] :usbcore:usb_unbind_interface+0x6d/0xe0
> Dec 23 23:27:04 cabrio kernel: [__device_release_driver+130/192]
> __device_release_driver+0x82/0xc0
> Dec 23 23:27:04 cabrio kernel: [device_release_driver+51/96]
> device_release_driver+0x33/0x60
> Dec 23 23:27:04 cabrio kernel: [bus_remove_device+118/176]
> bus_remove_device+0x76/0xb0
> Dec 23 23:27:04 cabrio kernel: [device_del+417/736] device_del+0x1a1/0x2e0
> Dec 23 23:27:04 cabrio kernel:
> [_end+128198657/2130651808] :usbcore:usb_disable_device+0x91/0x110
> Dec 23 23:27:04 cabrio kernel:
> [_end+128179466/2130651808] :usbcore:usb_disconnect+0xaa/0x150
> Dec 23 23:27:04 cabrio kernel:
> [_end+128181649/2130651808] :usbcore:hub_thread+0x401/0xe30
> Dec 23 23:27:04 cabrio kernel: [thread_return+87/1463]
> thread_return+0x57/0x5b7
> Dec 23 23:27:04 cabrio kernel: [autoremove_wake_function+0/48]
> autoremove_wake_function+0x0/0x30
> Dec 23 23:27:04 cabrio kernel:
> [_end+128180624/2130651808] :usbcore:hub_thread+0x0/0xe30
> Dec 23 23:27:04 cabrio kernel: [kthread+75/128] kthread+0x4b/0x80
> Dec 23 23:27:04 cabrio kernel: [child_rip+10/18] child_rip+0xa/0x12
> Dec 23 23:27:04 cabrio kernel: [kthread+0/128] kthread+0x0/0x80
> Dec 23 23:27:04 cabrio kernel: [child_rip+0/18] child_rip+0x0/0x12
> Dec 23 23:27:04 cabrio kernel:
> Dec 23 23:27:04 cabrio kernel:
> Dec 23 23:27:04 cabrio kernel: Code: 48 8b 03 0f 18 08 48 39 eb 75 ca 4c 89 ef
> e8 d2 35 fd f7 ba
> Dec 23 23:27:04 cabrio kernel: RSP <ffff810037bfdc40>
>
> Is there a way to exchange USB audio devices without rebooting?

First we have to work out if it's a USB bug or an ALSA bug. I'd guess
ALSA, but not with a lot of confidence.

Anyone?

2007-12-26 03:42:18

by Alan Stern

[permalink] [raw]
Subject: Re: Can't disconnect a USB sound device and connect another

On Tue, 25 Dec 2007, Andrew Morton wrote:

> On Sun, 23 Dec 2007 23:36:11 +0100 Victor Hahn <[email protected]> wrote:
>
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
> > ... because it causes lsusb to freeze and gives me this in /var/log/messages:
>
> Has this always happened, or is it something we introduced in a recent
> kernel?
>
> > Dec 23 23:27:04 cabrio kernel: usb 2-2: USB disconnect, address 5
> > Dec 23 23:27:04 cabrio kernel: PGD 110f2067 PUD 110f3067 PMD 0
> > Dec 23 23:27:04 cabrio kernel: CPU 0
> > Dec 23 23:27:04 cabrio kernel: Modules linked in: videodev v4l2_common
> > v4l1_compat snd_rtctimer binfmt_misc rfcomm l2cap bluetooth capability
...
> > Dec 23 23:27:04 cabrio kernel: Pid: 2052, comm: khubd Not tainted 2.6.23.11 #1
> > Dec 23 23:27:04 cabrio kernel: RIP: 0010:[_end+130488219/2130651808]
> > [_end+130488219/2130651808] :snd:snd_ctl_dev_disconnect+0x6b/0xb0
> > Dec 23 23:27:04 cabrio kernel: RSP: 0018:ffff810037bfdc40 EFLAGS: 00010282
> > Dec 23 23:27:04 cabrio kernel: RAX: 0000000000000000 RBX: 0000000000100100
> > RCX: 0000000000000018
> > Dec 23 23:27:04 cabrio kernel: RDX: 0000000000020004 RSI: 000000000000001d
> > RDI: ffff810013e98c08
> > Dec 23 23:27:04 cabrio kernel: RBP: ffff8100394631a8 R08: ffff810037bfc000
> > R09: 0000000000000000
...
> > Dec 23 23:27:04 cabrio kernel: Process khubd (pid: 2052, threadinfo
> > ffff810037bfc000, task ffff81003d67d0c0)
> > Dec 23 23:27:04 cabrio kernel: Stack: 0000000000000000 ffff810038850d00
> > ffff810039463000 ffff810039463150
> > Dec 23 23:27:04 cabrio kernel: 0000000000000000 ffffffff88281e69
> > ffff810038850d00 ffffffff882821ac
> > Dec 23 23:27:04 cabrio kernel: 0000000000000000 0000000000000000
> > ffff810039463000 ffff8100394631e0
> > Dec 23 23:27:04 cabrio kernel: Call Trace:
> > Dec 23 23:27:04 cabrio kernel:
> > [_end+130500873/2130651808] :snd:snd_device_disconnect+0x59/0x90
> > Dec 23 23:27:04 cabrio kernel:
...
> > Is there a way to exchange USB audio devices without rebooting?
>
> First we have to work out if it's a USB bug or an ALSA bug. I'd guess
> ALSA, but not with a lot of confidence.
>
> Anyone?

There have been similar reports of this bug. To me it looks like an
ALSA problem. The routine in question, snd_ctl_dev_disconnect(), is an
ALSA callback and doesn't contain any USB code.

A good way to start would be to obtain a disassembly listing of that
routine, so we can find out what C statement caused the bug.

Alan Stern

2007-12-31 20:03:49

by Alan Stern

[permalink] [raw]
Subject: Re: Can't disconnect a USB sound device and connect another

On Tue, 25 Dec 2007, Andrew Morton wrote:

> On Sun, 23 Dec 2007 23:36:11 +0100 Victor Hahn <[email protected]> wrote:
>
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
> > ... because it causes lsusb to freeze and gives me this in /var/log/messages:
>
> Has this always happened, or is it something we introduced in a recent
> kernel?
>
> > Dec 23 23:27:04 cabrio kernel: usb 2-2: USB disconnect, address 5
> > Dec 23 23:27:04 cabrio kernel: PGD 110f2067 PUD 110f3067 PMD 0
> > Dec 23 23:27:04 cabrio kernel: CPU 0
> > Dec 23 23:27:04 cabrio kernel: Modules linked in: videodev v4l2_common
> > v4l1_compat snd_rtctimer binfmt_misc rfcomm l2cap bluetooth capability
> > commoncap ppdev powernow_k8 cpufreq_userspace cpufreq_stats cpufreq_powersave
> > cpufreq_ondemand freq_table cpufreq_conservative video output sbs container
> > dock ac battery ext3 jbd mbcache aes_x86_64 ipv6 it87 hwmon_vid parport_pc lp
> > parport loop snd_mpu401 snd_mpu401_uart snd_usb_audio snd_pcm_oss
> > snd_mixer_oss snd_pcm snd_seq_dummy snd_page_alloc snd_usb_lib snd_hwdep
> > snd_seq_oss analog gameport snd_seq_midi snd_rawmidi snd_seq_midi_event
> > snd_seq snd_timer snd_seq_device snd psmouse button soundcore serio_raw
> > i2c_nforce2 k8temp i2c_core pcspkr af_packet shpchp pci_hotplug evdev xfs
> > sha256 twofish_x86_64 twofish_common cbc blkcipher sg ide_cd cdrom sd_mod
> > usbhid hid sata_nv 8139too floppy ata_generic 8139cp mii libata scsi_mod
> > amd74xx ide_core forcedeth ehci_hcd ohci_hcd usbcore dm_crypt dm_mirror
> > dm_snapshot dm_mod thermal processor fan fuse
> > Dec 23 23:27:04 cabrio kernel: Pid: 2052, comm: khubd Not tainted 2.6.23.11 #1
> > Dec 23 23:27:04 cabrio kernel: RIP: 0010:[_end+130488219/2130651808]
> > [_end+130488219/2130651808] :snd:snd_ctl_dev_disconnect+0x6b/0xb0
> > Dec 23 23:27:04 cabrio kernel: RSP: 0018:ffff810037bfdc40 EFLAGS: 00010282
> > Dec 23 23:27:04 cabrio kernel: RAX: 0000000000000000 RBX: 0000000000100100
> > RCX: 0000000000000018
> > Dec 23 23:27:04 cabrio kernel: RDX: 0000000000020004 RSI: 000000000000001d
> > RDI: ffff810013e98c08
> > Dec 23 23:27:04 cabrio kernel: RBP: ffff8100394631a8 R08: ffff810037bfc000
> > R09: 0000000000000000
> > Dec 23 23:27:04 cabrio kernel: R10: 0000000000000000 R11: ffffffff88281910
> > R12: ffff810039463000
> > Dec 23 23:27:04 cabrio kernel: R13: ffff810039463168 R14: 0000000000000000
> > R15: ffff810039463000
> > Dec 23 23:27:04 cabrio kernel: FS: 00002b24912551e0(0000) GS:ffffffff80533000
> > (0000) knlGS:00000000f74b16c0
> > Dec 23 23:27:04 cabrio kernel: CS: 0010 DS: 0018 ES: 0018 CR0:
> > 000000008005003b
> > Dec 23 23:27:04 cabrio kernel: CR2: 0000000000100100 CR3: 00000000110f1000
> > CR4: 00000000000006e0
> > Dec 23 23:27:04 cabrio kernel: DR0: 0000000000000000 DR1: 0000000000000000
> > DR2: 0000000000000000
> > Dec 23 23:27:04 cabrio kernel: DR3: 0000000000000000 DR6: 00000000ffff0ff0
> > DR7: 0000000000000400
> > Dec 23 23:27:04 cabrio kernel: Process khubd (pid: 2052, threadinfo
> > ffff810037bfc000, task ffff81003d67d0c0)
> > Dec 23 23:27:04 cabrio kernel: Stack: 0000000000000000 ffff810038850d00
> > ffff810039463000 ffff810039463150
> > Dec 23 23:27:04 cabrio kernel: 0000000000000000 ffffffff88281e69
> > ffff810038850d00 ffffffff882821ac
> > Dec 23 23:27:04 cabrio kernel: 0000000000000000 0000000000000000
> > ffff810039463000 ffff8100394631e0
> > Dec 23 23:27:04 cabrio kernel: Call Trace:
> > Dec 23 23:27:04 cabrio kernel:
> > [_end+130500873/2130651808] :snd:snd_device_disconnect+0x59/0x90
> > Dec 23 23:27:04 cabrio kernel:
> > [_end+130501708/2130651808] :snd:snd_device_disconnect_all+0x3c/0x70
> > Dec 23 23:27:04 cabrio kernel:
> > [_end+130481675/2130651808] :snd:snd_card_disconnect+0x15b/0x1a0
> > Dec 23 23:27:04 cabrio kernel:
> > [_end+131093678/2130651808] :snd_usb_audio:usb_audio_disconnect+0xae/0x1a0
> > Dec 23 23:27:04 cabrio kernel:
> > [_end+128211869/2130651808] :usbcore:usb_unbind_interface+0x6d/0xe0
> > Dec 23 23:27:04 cabrio kernel: [__device_release_driver+130/192]
> > __device_release_driver+0x82/0xc0
> > Dec 23 23:27:04 cabrio kernel: [device_release_driver+51/96]
> > device_release_driver+0x33/0x60
> > Dec 23 23:27:04 cabrio kernel: [bus_remove_device+118/176]
> > bus_remove_device+0x76/0xb0
> > Dec 23 23:27:04 cabrio kernel: [device_del+417/736] device_del+0x1a1/0x2e0
> > Dec 23 23:27:04 cabrio kernel:
> > [_end+128198657/2130651808] :usbcore:usb_disable_device+0x91/0x110
> > Dec 23 23:27:04 cabrio kernel:
> > [_end+128179466/2130651808] :usbcore:usb_disconnect+0xaa/0x150
> > Dec 23 23:27:04 cabrio kernel:
> > [_end+128181649/2130651808] :usbcore:hub_thread+0x401/0xe30
> > Dec 23 23:27:04 cabrio kernel: [thread_return+87/1463]
> > thread_return+0x57/0x5b7
> > Dec 23 23:27:04 cabrio kernel: [autoremove_wake_function+0/48]
> > autoremove_wake_function+0x0/0x30
> > Dec 23 23:27:04 cabrio kernel:
> > [_end+128180624/2130651808] :usbcore:hub_thread+0x0/0xe30
> > Dec 23 23:27:04 cabrio kernel: [kthread+75/128] kthread+0x4b/0x80
> > Dec 23 23:27:04 cabrio kernel: [child_rip+10/18] child_rip+0xa/0x12
> > Dec 23 23:27:04 cabrio kernel: [kthread+0/128] kthread+0x0/0x80
> > Dec 23 23:27:04 cabrio kernel: [child_rip+0/18] child_rip+0x0/0x12
> > Dec 23 23:27:04 cabrio kernel:
> > Dec 23 23:27:04 cabrio kernel:
> > Dec 23 23:27:04 cabrio kernel: Code: 48 8b 03 0f 18 08 48 39 eb 75 ca 4c 89 ef
> > e8 d2 35 fd f7 ba
> > Dec 23 23:27:04 cabrio kernel: RSP <ffff810037bfdc40>
> >
> > Is there a way to exchange USB audio devices without rebooting?
>
> First we have to work out if it's a USB bug or an ALSA bug. I'd guess
> ALSA, but not with a lot of confidence.
>
> Anyone?

See

http://bugzilla.kernel.org/show_bug.cgi?id=9196

This looks the same as that.

Alan Stern