This has been broken for a long time.
Symtoms: programs using the card while it is disconnected get stuck and cannot be killed, and OOPS is printed on the log:
[108034.041573] usb 9-2: USB disconnect, address 3 [108043.576040] usb 9-2: new full speed USB device using uhci_hcd and address 4 [108043.757185] usb 9-2: configuration #1 chosen from 1 choice [108057.602616] BUG: unable to handle kernel paging request at 000061d855001080 [108057.602621] IP: [<ffffffffa00e0c71>] hcd_buffer_free+0x11/0x90 [usbcore] [108057.602643] PGD 0 [108057.602647] Oops: 0000 [1] SMP [108057.602652] CPU 0 [108057.602655] Modules linked in: nls_cp437 cifs af_packet binfmt_misc rfcomm l2cap bluetooth ppdev ipv6 cpufreq_conservative cpufreq_ondemand cpufreq_powersave cpufreq_userspace cpufreq_stats freq_table container video output sbs sbshc pci_slot wmi battery iptable_filter ip_tables x_tables ext2 ac lp loop snd_seq_dummy arc4 snd_hda_intel snd_seq_oss ecb crypto_blkcipher snd_usb_audio snd_usb_lib snd_pcm_oss snd_mixer_oss snd_seq_midi snd_pcm snd_rawmidi ath9k snd_seq_midi_event snd_hwdep snd_seq mac80211 psmouse snd_timer snd_seq_device cfg80211 snd serio_raw iTCO_wdt iTCO_vendor_support soundcore nvidia(P) snd_page_alloc i2c_core parport_pc parport button shpchp pci_hotplug intel_agp evdev joydev ext3 jbd mbcache sg sd_mod crc_t10dif ata_generic ata_piix pata_jmicron usbhid hid pata_acpi ahci libata scsi_mod dock sky2 uhci_hcd ehci_hcd usbcore raid10 raid456 async_xor async_memcpy async_tx xor raid1 raid0 multipath linear md_mod thermal processor fan fbcon tileblit font bitblit softcursor uvesafb cn fuse [108057.602714] Pid: 15655, comm: rhythmbox Tainted: P 2.6.27-3-generic #1 [108057.602716] RIP: 0010:[<ffffffffa00e0c71>] [<ffffffffa00e0c71>] hcd_buffer_free+0x11/0x90 [usbcore] [108057.602727] RSP: 0018:ffff8801a7d97cc8 EFLAGS: 00010286 [108057.602729] RAX: ffff880219061680 RBX: ffff88021a162e00 RCX: 0000000037836060 [108057.602731] RDX: ffff880037836060 RSI: 0000000000000020 RDI: 000061d855001080 [108057.602733] RBP: ffff8801a7d97cc8 R08: ffff880037836060 R09: 0000000000000566 [108057.602734] R10: 0000000000000002 R11: 0000000000000000 R12: ffff88021a1630c8 [108057.602736] R13: 0000000000001fff R14: ffff88021a44e400 R15: 0000000000000000 [108057.602738] FS: 00007ffd6f42f7a0(0000) GS:ffffffff806ffa80(0000) knlGS:0000000000000000 [108057.602740] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [108057.602742] CR2: 000061d855001080 CR3: 00000001d80ff000 CR4: 00000000000006e0 [108057.602744] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [108057.602745] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [108057.602747] Process rhythmbox (pid: 15655, threadinfo ffff8801a7d96000, task ffff8801c68cd9c0) [108057.602749] Stack: ffff8801a7d97cd8 ffffffffa00d3425 ffff8801a7d97cf8 ffffffffa0b391d5 [108057.602754] ffff88021aa00c00 ffff88021aa00c00 ffff8801a7d97d18 ffffffffa0b39212 [108057.602758] ffff88021a163000 ffff88021a163000 ffff8801a7d97d28 ffffffffa0b39275 [108057.602761] Call Trace: [108057.602775] [<ffffffffa00d3425>] usb_buffer_free+0x25/0x30 [usbcore] [108057.602780] [<ffffffffa0b391d5>] snd_usbmidi_out_endpoint_delete+0x35/0x50 [snd_usb_lib] [108057.602784] [<ffffffffa0b39212>] snd_usbmidi_free+0x22/0x70 [snd_usb_lib] [108057.602787] [<ffffffffa0b39275>] snd_usbmidi_rawmidi_free+0x15/0x20 [snd_usb_lib] [108057.602792] [<ffffffffa0af9287>] snd_rawmidi_free+0xf7/0x110 [snd_rawmidi] [108057.602796] [<ffffffffa0af92b2>] snd_rawmidi_dev_free+0x12/0x20 [snd_rawmidi] [108057.602805] [<ffffffffa0a1a8b1>] snd_device_free+0x71/0xd0 [snd] [108057.602811] [<ffffffffa0a1a974>] snd_device_free_all+0x64/0x70 [snd] [108057.602818] [<ffffffffa0a14a1f>] snd_card_do_free+0x3f/0xe0 [snd] [108057.602824] [<ffffffffa0a14bff>] snd_card_file_remove+0x13f/0x170 [snd] [108057.602833] [<ffffffffa0b09f86>] snd_pcm_release+0xa6/0xc0 [snd_pcm] [108057.602839] [<ffffffffa0a15630>] ? snd_disconnect_release+0x0/0xb0 [snd] [108057.602846] [<ffffffffa0a156a6>] snd_disconnect_release+0x76/0xb0 [snd] [108057.602852] [<ffffffff802ec8a9>] __fput+0xc9/0x1b0 [108057.602854] [<ffffffff802ec9b5>] fput+0x25/0x30 [108057.602858] [<ffffffff802c67e3>] remove_vma+0x43/0x90 [108057.602860] [<ffffffff802c860a>] do_munmap+0x2ea/0x330 [108057.602862] [<ffffffff802c86a5>] sys_munmap+0x55/0x80 [108057.602866] [<ffffffff8021288a>] system_call_fastpath+0x16/0x1b [108057.602868] [108057.602869] [108057.602870] Code: 07 48 ff 84 02 00 02 00 00 4c 89 f1 49 89 4d 20 eb 9f 90 90 90 90 90 90 90 90 55 48 89 e5 0f 1f 44 00 00 48 85 d2 49 89 d0 74 3b <48> 8b 07 48 83 b8 c0 01 00 00 00 74 52 48 c7 c2 20 90 0e a0 31 [108057.602896] RIP [<ffffffffa00e0c71>] hcd_buffer_free+0x11/0x90 [usbcore] [108057.602907] RSP <ffff8801a7d97cc8> [108057.602909] CR2: 000061d855001080 [108057.602917] ---[ end trace 8c6a5ea5cd36c92b ]---
asound.conf:
# Allow mixing of multiple output streams to this device pcm.output { type dmix ipc_key 1024 ipc_perm 0660 # Sound for everybody in your group! slave.pcm "hw:UA25"
slave { # This stuff provides some fixes for latency issues. # buffer_size should be set for your audio chipset. period_time 0 period_size 1024 buffer_size 8192 rate 48000 }
bindings { 0 0 1 1 } }
pcm.!default { type plug slave.pcm "output" slave.rate 48000 }
uname -a: Linux Kaidenn 2.6.27-3-generic #1 SMP Wed Sep 10 16:18:52 UTC 2008 x86_64 GNU/Linux
And yes, I know that it is tainted. Live with it.