usbmc seems broken

From: Neil Kalo
Date: Fri Jan 22 2010 - 11:40:18 EST


I cannot get usbtmc to work with my device. I am using fedora 12:
2.6.31.12-174.2.3.fc12.i686.PAE

Jan 22 15:40:26 localhost kernel: usb 4-1: new full speed USB device
using ohci_hcd and address 4
Jan 22 15:40:26 localhost kernel: usb 4-1: New USB device found,
idVendor=05e6, idProduct=2100
Jan 22 15:40:26 localhost kernel: usb 4-1: New USB device strings:
Mfr=2, Product=3, SerialNumber=1
Jan 22 15:40:26 localhost kernel: usb 4-1: Product: 2100 Multimeter
Jan 22 15:40:26 localhost kernel: usb 4-1: Manufacturer: KEITHLEY INSTRUMENTS
Jan 22 15:40:26 localhost kernel: usb 4-1: SerialNumber: 1160791
Jan 22 15:40:26 localhost kernel: usb 4-1: configuration #1 chosen from 1 choice
Jan 22 15:40:26 localhost kernel: usbtmc 4-1:1.0: can't read capabilities

If I compile the original Agilent module from
"http://www.home.agilent.com/upload/cmc_upload/All/usbtmc.html"; It
works fine:

Jan 22 15:37:45 localhost kernel: usb 4-1: new full speed USB device
using ohci_hcd and address 3
Jan 22 15:37:45 localhost kernel: usb 4-1: New USB device found,
idVendor=05e6, idProduct=2100
Jan 22 15:37:45 localhost kernel: usb 4-1: New USB device strings:
Mfr=2, Product=3, SerialNumber=1
Jan 22 15:37:45 localhost kernel: usb 4-1: Product: 2100 Multimeter
Jan 22 15:37:45 localhost kernel: usb 4-1: Manufacturer: KEITHLEY INSTRUMENTS
Jan 22 15:37:45 localhost kernel: usb 4-1: SerialNumber: 1160791
Jan 22 15:37:45 localhost kernel: usb 4-1: configuration #1 chosen from 1 choice
Jan 22 15:37:45 localhost kernel: USBTMC: MKDEV
Jan 22 15:37:45 localhost kernel: USBTMC: CDEV_ADD f900000 1

Note that I do get one error line per module load, but this does not
prevent the device from working in my application:
Jan 22 15:38:21 localhost kernel: USBTMC: Unable to read data, error -110

This error also sometimes occurs with the standard kernel module, but
I never get a functioning connection to my device:
Jan 16 23:43:36 localhost kernel: usbtmc 1-4.1.1:1.0: can't read capabilities
Jan 16 23:52:31 localhost kernel: usbtmc 1-4.1.1:1.0: Unable to read
data, error -110

Where do I go from here?
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