[Pyusb-users] Unknown error trying to getString from devices on OSX

[Yaniv A. <ya...@ak...>]

Hi,

I'm trying to use PyUSB on OSX (10.4.10) to enumerate USB devices. I'm not
entirely certain why, but upon calling getString on a device (almost any
device on my system at least, and I have a few), I'm getting a USBError,
with usb_control_msg: unknown error.

My (slightly modified) lsusb.py source is:

osx:pyusb yaniv$ cat lsusb.py
#!/usr/bin/env python

import usb
import sys

for bus in usb.busses():
        for dev in bus.devices:
                try:
                        print "Bus %s Device %s: ID %04x:%04x %s" % (
bus.dirname,dev.filename,dev.idVendor,dev.idProduct,dev.open
().getString(1,30))
                except:
                        print 'caught ', sys.exc_info()[1]
                        continue
osx:pyusb yaniv$ ./lsusb.py
caught usb_control_msg(DeviceRequestTO): unknown error
caught usb_control_msg(DeviceRequestTO): unknown error
caught usb_control_msg(DeviceRequestTO): unknown error
caught usb_control_msg(DeviceRequestTO): unknown error
caught usb_control_msg(DeviceRequestTO): unknown error
caught usb_control_msg(DeviceRequestTO): unknown error
caught usb_control_msg(DeviceRequestTO): pipe is stalled
caught usb_control_msg(DeviceRequestTO): pipe is stalled
Bus 005 Device 002-05ac-8501-ff-ff: ID 05ac:8501 Micron
caught usb_control_msg(DeviceRequestTO): pipe is stalled
osx:pyusb yaniv$

The exception is caught on the getString(), not on the open().

I don't know what's special about this Micron device which works.

I've tried running as UID 0 as well.

Any further ideas?

Many thanks,
 - Yaniv