[BRLTTY] Occasional, intermittent, USB problem

[Jason White]

Most of the necessary information should be in the log entries below. This is
a Debian kernel 2.6.25-2-amd64 #1 SMP Mon Jul 14 11:05:23 UTC 2008 x86_64

I have occasionally noticed this with earlier kernels.

Is it a hardware or a software problem? The user visible symptom, apart from
the log entries, is that the braille display becomes unusable for a few
seconds, then the BRLTTY Baum driver is re-initialized successfully.

this only seems to happen on my desktop system, leading to the suspicion that
it's either hardware, or something related to the specific USB controller in
use. This is an Intel Corporation 631xESB/632xESB/3100 Chipset UHCI USB
Controller, according to lshw.

Jul 29 15:50:53 jdc brltty[2442]: USB URB status error 84: Invalid or incomplete multibyte or wide character.
Jul 29 15:50:53 jdc brltty[2442]: USB URB status error 84: Invalid or incomplete multibyte or wide character.
Jul 29 15:50:53 jdc brltty[2442]: USB URB status error 84: Invalid or incomplete multibyte or wide character.
Jul 29 15:50:53 jdc brltty[2442]: USB URB status error 84: Invalid or incomplete multibyte or wide character.
Jul 29 15:50:53 jdc brltty[2442]: USB URB status error 84: Invalid or incomplete multibyte or wide character.
Jul 29 15:50:53 jdc brltty[2442]: USB URB status error 84: Invalid or incomplete multibyte or wide character.
Jul 29 15:50:53 jdc brltty[2442]: USB URB status error 84: Invalid or incomplete multibyte or wide character.
Jul 29 15:50:53 jdc brltty[2442]: USB URB status error 84: Invalid or incomplete multibyte or wide character.
Jul 29 15:50:53 jdc brltty[2442]: USB URB status error 84: Invalid or incomplete multibyte or wide character.
Jul 29 15:50:53 jdc brltty[2442]: USB URB status error 84: Invalid or incomplete multibyte or wide character.
Jul 29 15:50:53 jdc brltty[2442]: USB URB status error 84: Invalid or incomplete multibyte or wide character.
Jul 29 15:50:53 jdc brltty[2442]: USB URB status error 84: Invalid or incomplete multibyte or wide character.
Jul 29 15:50:53 jdc brltty[2442]: USB URB status error 84: Invalid or incomplete multibyte or wide character.
Jul 29 15:50:53 jdc brltty[2442]: USB URB status error 84: Invalid or incomplete multibyte or wide character.
Jul 29 15:50:53 jdc brltty[2442]: USB URB status error 84: Invalid or incomplete multibyte or wide character.
Jul 29 15:50:53 jdc brltty[2442]: USB URB status error 84: Invalid or incomplete multibyte or wide character.
Jul 29 15:50:53 jdc kernel: [ 1639.232166] usb 4-2: USB disconnect, address 2
Jul 29 15:50:53 jdc brltty[2442]: USB URB reap error 19: No such device.
Jul 29 15:50:53 jdc kernel: [ 1639.324189] hub 5-0:1.0: unable to enumerate USB device on port 8
Jul 29 15:50:54 jdc kernel: [ 1929.842551] usb 4-2: new full speed USB device using uhci_hcd and address 3
Jul 29 15:50:54 jdc kernel: [ 2115.346325] usb 4-2: configuration #1 chosen from 1 choice
Jul 29 15:50:54 jdc kernel: [ 1929.867516] usb 4-2: New USB device found, idVendor=0403, idProduct=fe72
Jul 29 15:50:54 jdc kernel: [ 1929.867521] usb 4-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Jul 29 15:50:54 jdc kernel: [ 1929.867523] usb 4-2: Product: Brailliant 40
Jul 29 15:50:54 jdc kernel: [ 1929.867525] usb 4-2: Manufacturer: HumanWare
Jul 29 15:50:54 jdc kernel: [ 1929.867528] usb 4-2: SerialNumber: 25000072
Jul 29 15:50:59 jdc brltty[2442]: Ignored Byte: 80
Jul 29 15:50:59 jdc brltty[2442]: Ignored Byte: 00
Jul 29 15:50:59 jdc brltty[2442]: Ignored Byte: 00
Jul 29 15:50:59 jdc brltty[2442]: Ignored Byte: 00
Jul 29 15:50:59 jdc brltty[2442]: Ignored Byte: 00
Jul 29 15:50:59 jdc brltty[2442]: Ignored Byte: 00
Jul 29 15:50:59 jdc brltty[2442]: Ignored Byte: 00
Jul 29 15:50:59 jdc brltty[2442]: Ignored Byte: 00
Jul 29 15:50:59 jdc brltty[2442]: Ignored Byte: 00
Jul 29 15:50:59 jdc brltty[2442]: Ignored Byte: 00
Jul 29 15:50:59 jdc brltty[2442]: Ignored Byte: 00
Jul 29 15:50:59 jdc brltty[2442]: Ignored Byte: 00
Jul 29 15:50:59 jdc brltty[2442]: Ignored Byte: 00
Jul 29 15:50:59 jdc brltty[2442]: Ignored Byte: 00
Jul 29 15:50:59 jdc brltty[2442]: Ignored Byte: 00
Jul 29 15:50:59 jdc brltty[2442]: Ignored Byte: 00
Jul 29 15:50:59 jdc brltty[2442]: Baum Braille Driver: