Got several of these messages when I plugged in a usb gps unit. The
gps unit worked fine.

Also, the gspca driver works for my web cams now. Very nice to have
that in the kernel. Thanks to all those who worked on it!

Longer log attached.

usb 6-2: pl2303 converter now attached to ttyUSB0
usbcore: registered new interface driver pl2303
pl2303: Prolific PL2303 USB to serial adaptor driver
------------[ cut here ]------------
WARNING: at drivers/usb/serial/usb-serial.c:311 serial_write+0x9c/0xa0
[usbserial]()
Modules linked in: pl2303 usbserial gspca_spca561 gspca_main
acpi_cpufreq nfsd auth_rpcgss exportfs kvm_intel kvm nfs lockd sunrpc
twofish twofish_common serpent blowfish aes_i586 aes_generic xcbc
sha256_generic crypto_null af_key dm_snapshot dm_mirror dm_log
coretemp w83627ehf hwmon_vid sg joydev usbhid snd_hda_intel
snd_pcm_oss snd_mixer_oss snd_pcm snd_timer snd pata_jmicron ata_piix
i2c_i801 ahci ehci_hcd soundcore r8169 uhci_hcd snd_page_alloc usbcore
[last unloaded: pcspkr]
Pid: 7, comm: events/0 Not tainted 2.6.27-rc5.1-00341-gf98ef8e-dirty #1
[<40125e74>] warn_on_slowpath+0x54/0x70
[<4011a787>] ? hrtick_start_fair+0x1a7/0x1b0
[<4011bea3>] ? enqueue_task_fair+0x33/0x2c0
[<401236f6>] ? check_preempt_wakeup+0x106/0x180
[<4020adf9>] ? rb_insert_color+0x99/0xc0
[<4013b5d5>] ? enqueue_hrtimer+0x75/0x100
[<c0a9d43c>] serial_write+0x9c/0xa0 [usbserial]
[<4013bcbe>] ? hrtimer_start+0xae/0x130
[<4024fddb>] tty_put_char+0x2b/0x40
[<4011a75e>] ? hrtick_start_fair+0x17e/0x1b0
[<40253f59>] echo_char+0x49/0x70
[<40254c5f>] n_tty_receive_buf+0x6cf/0x1180
[<40207025>] ? __next_cpu+0x15/0x30
[<4011c664>] ? find_busiest_group+0x134/0x6d0
[<4011934d>] ? update_curr+0x8d/0xc0
[<4011a36a>] ? __dequeue_entity+0x2a/0xa0
[<401228e4>] ? dequeue_task_fair+0xa4/0x110
[<40256eb5>] ? tty_ldisc_try+0x35/0x50
[<4025086d>] flush_to_ldisc+0xdd/0x190
[<40254590>] ? n_tty_receive_buf+0x0/0x1180
[<40250790>] ? flush_to_ldisc+0x0/0x190
[<401352f7>] run_workqueue+0x77/0x100
[<40138a43>] ? prepare_to_wait+0x53/0x60
[<40135c89>] worker_thread+0x99/0xf0
[<40138870>] ? autoremove_wake_function+0x0/0x50
[<40135bf0>] ? worker_thread+0x0/0xf0
[<40138572>] kthread+0x42/0x70
[<40138530>] ? kthread+0x0/0x70
[<40103d63>] kernel_thread_helper+0x7/0x14
=======================
---[ end trace 68b706884af5ac09 ]---
ttyS0: LSR safety check engaged!
ttyS1: LSR safety check engaged!
Installing knfsd (copyright (C) 1996 okir@monad.swb.de).
NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
NFSD: starting 90-second grace period
warning: `ntpd' uses 32-bit capabilities (legacy support in use)
usb 4-1: new full speed USB device using uhci_hcd and address 2
usb 4-1: configuration #1 chosen from 1 choice
gspca: main v2.2.0 registered
gspca: probing 04fc:0561
gspca: probe ok
usbcore: registered new interface driver spca561
spca561: registered
usb 4-1: USB disconnect, address 2
gspca: disconnect complete
usb 4-1: new full speed USB device using uhci_hcd and address 3
usb 4-1: configuration #1 chosen from 1 choice
gspca: probing 046d:0928
gspca: probe ok
usb 5-1: new full speed USB device using uhci_hcd and address 4
usb 5-1: configuration #1 chosen from 1 choice
gspca: probing 04fc:0561
gspca: probe ok
gspca: usb_submit_urb [0] err -28
gspca: usb_submit_urb [0] err -28
hda-intel: IRQ timing workaround is activated for card #0. Suggest a bigger bdl_pos_adj.
usb 6-2: new full speed USB device using uhci_hcd and address 2
usb 6-2: configuration #1 chosen from 1 choice
usbcore: registered new interface driver usbserial
usbserial: USB Serial Driver core
usbserial: USB Serial support registered for pl2303
pl2303 6-2:1.0: pl2303 converter detected
usb 6-2: pl2303 converter now attached to ttyUSB0
usbcore: registered new interface driver pl2303
pl2303: Prolific PL2303 USB to serial adaptor driver
------------[ cut here ]------------
WARNING: at drivers/usb/serial/usb-serial.c:311 serial_write+0x9c/0xa0 [usbserial]()
Modules linked in: pl2303 usbserial gspca_spca561 gspca_main acpi_cpufreq nfsd auth_rpcgss exportfs kvm_intel kvm nfs lockd sunrpc twofish twofish_common serpent blowfish aes_i586 aes_generic xcbc sha256_generic crypto_null af_key dm_snapshot dm_mirror dm_log coretemp w83627ehf hwmon_vid sg joydev usbhid snd_hda_intel snd_pcm_oss snd_mixer_oss snd_pcm snd_timer snd pata_jmicron ata_piix i2c_i801 ahci ehci_hcd soundcore r8169 uhci_hcd snd_page_alloc usbcore [last unloaded: pcspkr]
Pid: 7, comm: events/0 Not tainted 2.6.27-rc5.1-00341-gf98ef8e-dirty #1
 [<40125e74>] warn_on_slowpath+0x54/0x70
 [<4011a787>] ? hrtick_start_fair+0x1a7/0x1b0
 [<4011bea3>] ? enqueue_task_fair+0x33/0x2c0
 [<401236f6>] ? check_preempt_wakeup+0x106/0x180
 [<4020adf9>] ? rb_insert_color+0x99/0xc0
 [<4013b5d5>] ? enqueue_hrtimer+0x75/0x100
 [<c0a9d43c>] serial_write+0x9c/0xa0 [usbserial]
 [<4013bcbe>] ? hrtimer_start+0xae/0x130
 [<4024fddb>] tty_put_char+0x2b/0x40
 [<4011a75e>] ? hrtick_start_fair+0x17e/0x1b0
 [<40253f59>] echo_char+0x49/0x70
 [<40254c5f>] n_tty_receive_buf+0x6cf/0x1180
 [<40207025>] ? __next_cpu+0x15/0x30
 [<4011c664>] ? find_busiest_group+0x134/0x6d0
 [<4011934d>] ? update_curr+0x8d/0xc0
 [<4011a36a>] ? __dequeue_entity+0x2a/0xa0
 [<401228e4>] ? dequeue_task_fair+0xa4/0x110
 [<40256eb5>] ? tty_ldisc_try+0x35/0x50
 [<4025086d>] flush_to_ldisc+0xdd/0x190
 [<40254590>] ? n_tty_receive_buf+0x0/0x1180
 [<40250790>] ? flush_to_ldisc+0x0/0x190
 [<401352f7>] run_workqueue+0x77/0x100
 [<40138a43>] ? prepare_to_wait+0x53/0x60
 [<40135c89>] worker_thread+0x99/0xf0
 [<40138870>] ? autoremove_wake_function+0x0/0x50
 [<40135bf0>] ? worker_thread+0x0/0xf0
 [<40138572>] kthread+0x42/0x70
 [<40138530>] ? kthread+0x0/0x70
 [<40103d63>] kernel_thread_helper+0x7/0x14
 =======================
---[ end trace 68b706884af5ac09 ]---
------------[ cut here ]------------
WARNING: at drivers/usb/serial/usb-serial.c:311 serial_write+0x9c/0xa0 [usbserial]()
Modules linked in: pl2303 usbserial gspca_spca561 gspca_main acpi_cpufreq nfsd auth_rpcgss exportfs kvm_intel kvm nfs lockd sunrpc twofish twofish_common serpent blowfish aes_i586 aes_generic xcbc sha256_generic crypto_null af_key dm_snapshot dm_mirror dm_log coretemp w83627ehf hwmon_vid sg joydev usbhid snd_hda_intel snd_pcm_oss snd_mixer_oss snd_pcm snd_timer snd pata_jmicron ata_piix i2c_i801 ahci ehci_hcd soundcore r8169 uhci_hcd snd_page_alloc usbcore [last unloaded: pcspkr]
Pid: 7, comm: events/0 Tainted: G        W 2.6.27-rc5.1-00341-gf98ef8e-dirty #1
 [<40125e74>] warn_on_slowpath+0x54/0x70
 [<40135a71>] ? __queue_work+0x31/0x40
 [<40135ae8>] ? queue_work_on+0x38/0x50
 [<40135b35>] ? queue_work+0x15/0x20
 [<40135b4f>] ? schedule_work+0xf/0x20
 [<c0a9d82d>] ? usb_serial_port_softint+0xd/0x10 [usbserial]
 [<c0aa5189>] ? pl2303_send+0x139/0x270 [pl2303]
 [<c0aa6285>] ? pl2303_write+0xe5/0x140 [pl2303]
 [<4020adf9>] ? rb_insert_color+0x99/0xc0
 [<c0a9d43c>] serial_write+0x9c/0xa0 [usbserial]
 [<4024fddb>] tty_put_char+0x2b/0x40
 [<4011a74f>] ? hrtick_start_fair+0x16f/0x1b0
 [<40253f66>] echo_char+0x56/0x70
 [<40254c5f>] n_tty_receive_buf+0x6cf/0x1180
 [<40207025>] ? __next_cpu+0x15/0x30
 [<4011c664>] ? find_busiest_group+0x134/0x6d0
 [<4011934d>] ? update_curr+0x8d/0xc0
 [<4011a36a>] ? __dequeue_entity+0x2a/0xa0
 [<401228e4>] ? dequeue_task_fair+0xa4/0x110
 [<40256eb5>] ? tty_ldisc_try+0x35/0x50
 [<4025086d>] flush_to_ldisc+0xdd/0x190
 [<40254590>] ? n_tty_receive_buf+0x0/0x1180
 [<40250790>] ? flush_to_ldisc+0x0/0x190
 [<401352f7>] run_workqueue+0x77/0x100
 [<40138a43>] ? prepare_to_wait+0x53/0x60
 [<40135c89>] worker_thread+0x99/0xf0
 [<40138870>] ? autoremove_wake_function+0x0/0x50
 [<40135bf0>] ? worker_thread+0x0/0xf0
 [<40138572>] kthread+0x42/0x70
 [<40138530>] ? kthread+0x0/0x70
 [<40103d63>] kernel_thread_helper+0x7/0x14
 =======================
---[ end trace 68b706884af5ac09 ]---
------------[ cut here ]------------
WARNING: at drivers/usb/serial/usb-serial.c:324 serial_write_room+0x75/0x80 [usbserial]()
Modules linked in: pl2303 usbserial gspca_spca561 gspca_main acpi_cpufreq nfsd auth_rpcgss exportfs kvm_intel kvm nfs lockd sunrpc twofish twofish_common serpent blowfish aes_i586 aes_generic xcbc sha256_generic crypto_null af_key dm_snapshot dm_mirror dm_log coretemp w83627ehf hwmon_vid sg joydev usbhid snd_hda_intel snd_pcm_oss snd_mixer_oss snd_pcm snd_timer snd pata_jmicron ata_piix i2c_i801 ahci ehci_hcd soundcore r8169 uhci_hcd snd_page_alloc usbcore [last unloaded: pcspkr]
Pid: 7, comm: events/0 Tainted: G        W 2.6.27-rc5.1-00341-gf98ef8e-dirty #1
 [<40125e74>] warn_on_slowpath+0x54/0x70
 [<40135a71>] ? __queue_work+0x31/0x40
 [<40135ae8>] ? queue_work_on+0x38/0x50
 [<40135b35>] ? queue_work+0x15/0x20
 [<40135b4f>] ? schedule_work+0xf/0x20
 [<c0aa519a>] ? pl2303_send+0x14a/0x270 [pl2303]
 [<c0aa6285>] ? pl2303_write+0xe5/0x140 [pl2303]
 [<4020adf9>] ? rb_insert_color+0x99/0xc0
 [<c0a9d395>] serial_write_room+0x75/0x80 [usbserial]
 [<40255e98>] tty_write_room+0x18/0x20
 [<40253d0a>] opost+0x1a/0x220
 [<40253f3d>] echo_char+0x2d/0x70
 [<40254c5f>] n_tty_receive_buf+0x6cf/0x1180
 [<40207025>] ? __next_cpu+0x15/0x30
 [<4011c664>] ? find_busiest_group+0x134/0x6d0
 [<4011934d>] ? update_curr+0x8d/0xc0
 [<4011a36a>] ? __dequeue_entity+0x2a/0xa0
 [<401228e4>] ? dequeue_task_fair+0xa4/0x110
 [<40256eb5>] ? tty_ldisc_try+0x35/0x50
 [<4025086d>] flush_to_ldisc+0xdd/0x190
 [<40254590>] ? n_tty_receive_buf+0x0/0x1180
 [<40250790>] ? flush_to_ldisc+0x0/0x190
 [<401352f7>] run_workqueue+0x77/0x100
 [<40138a43>] ? prepare_to_wait+0x53/0x60
 [<40135c89>] worker_thread+0x99/0xf0
 [<40138870>] ? autoremove_wake_function+0x0/0x50
 [<40135bf0>] ? worker_thread+0x0/0xf0
 [<40138572>] kthread+0x42/0x70
 [<40138530>] ? kthread+0x0/0x70
 [<40103d63>] kernel_thread_helper+0x7/0x14
 =======================
---[ end trace 68b706884af5ac09 ]---
...