On Tue, Dec 31, 2013 at 1:54 PM, Valentina Manea <valentina.manea.m@gmail.com> wrote:
Hi,
I am working on the USB/IP drivers in the staging directory and bumped into an issue with one of the drivers.
usbip-host is declared as struct usb_driver (so, an USB interface driver). My task was to transform it to struct usb_device_driver - in this way, instead of binding each interface to the driver, the whole device would be bound to the driver.
The binding is made from userspace via the bind file of the driver [1] and using libsysfs. With the old version of the driver, one would write something like 1-1:1.0 to bind interface 0 of device with bus ID 1-1.
However, with the new version of the driver, using the same syntax for device identification (1-1:1.0), this binding fails: * libsysfs doesn't give much info about the error * echo-ing the ID into bind file as shown in [1] doesn't work in either case; on the other hand, I can succesfully unbind the device from the default driver (usb-storage in this case) using the same mechanism * I have a printk in the probe function of the driver - it seems it doesn't even get there.
I am missing something but have no clue where to look anymore.
Thanks, Valentina
Just in case anyone ever bumps into the same problem, it seems there is a generic USB device driver (*device* driver, not *interface* device driver) that claims all the USB devices. So, one should first unbind from that driver; echo-ing the bus ID into /sys/bus/usb/drivers/usb/unbind will do.