On Wed, 8 Oct 2008, Throctukes wrote:
> I have a USB device (a custom device I'm trying to talk to) with two
> endpoints, one writing to the device, one reading from the device. Both are
> bulk transfers. Every communication transaction takes the form of (1) Write
> a command to the device (2) Read the response. I'm using libusb 0.1.12
>
> On Windows, all is well. I can connect the device, claim the interface and
> communicate happily. However, in Ubuntu (a standard Hardy desktop install),
> whilst I can connect to the device and write to it, all read operations fail
> with the error "error submitting URB: Invalid argument" reported from libusb
> (error code -22).
>
> If I check /var/log/messages I see a warning message logged for the same
> time as the read was attempted: "sysfs: duplicate filename 'usbdev4.3_ep81'
> can not be created" - which tallies with the device (it is indeed on that
> bus and it's endpoint 81 I'm trying to read from). Dunno if that's relevant.
>
> I've been trying to figure out what I'm doing wrong for days now - has
> anyone got any ideas where I should even be looking for the problem? I
> noticed that someone else reported a similar issue, but found that it was
> because their endpoint was really in interrupt, not bulk, mode. I'm pretty
> sure that's not the case here.
Firstly, it wouldn't hurt to use the most up-to-date kernel available.
That would be 2.6.27.
Secondly, you shouldn't expect us to be able to figure out problems
without any data. At the very least you need to post the kernel log.
You should also include more information about the device, such as its
entry in /proc/bus/usb/devices, or its "lsusb -v" entry.
Alan Stern
|
