Re: [Libusb-devel] usbfs: usb_submit_urb returned -121

[Alan S. <st...@ro...>]

On Thu, 24 Jun 2010, Ludovic Rousseau wrote:

> 2010/6/24 Alan Stern <st...@ro...>:
> > On Thu, 24 Jun 2010, Ludovic Rousseau wrote:
> >
> >> Hello,
> >>
> >> I try to stress my code by sending the same command on a loop. But I
> >> may be hit by a kernel bug or libusb bug.
> >> I am using libusb git version up-to-date and kernel 2.6.34-1-686 or
> >> vmlinuz-2.6.32-5-686 (from Debian). Both kernels have the problem.
> >>
> >> libusb returns -99 (LIBUSB_ERROR_OTHER) and the kernel logs a line in
> >> /var/log/syslog:
> >> Jun 24 15:08:01 trinity kernel: [  299.676480] usb 3-1.3: usbfs:
> >> usb_submit_urb returned -121
> >>
> >> I also used my previous kernel 2.6.26-2-686 from Debian stable and
> >> libusb-1.0.8 and I DO NOT have the problem. So it looks a bug in the
> >> recent kernels or in the way libusb is using the kernel.
> >
> > It is a bug in libusb.  It is caused by interaction with a kernel
> > feature that was added not long ago.  I forget when exactly, but after
> > 2.6.26.
> 
> An already  known bug. Cool.

That's not what I meant.  I'm not aware if this bug was known
previously -- certainly I never knew about it.  And if Daniel knew, he
would have fixed it already.

Your description made it clear what the source of the bug must be.  
That's all I was trying to say.

Alan Stern