speedtch usbatm.c,1.26,1.27

Duncan Sands baldrick at free.fr
Thu May 5 15:47:03 EDT 2005

On Thu, 2005-05-05 at 21:18 +0200, Duncan Sands wrote:
> > > But is it OK to resubmit straight away [...] ?
> > 
> > But we don't: it's always a "soft failure" path, when we only schedule
> > the resumption of the processing after our throttling delay.
> Yeah, and it's about the hundredth time I've forgotten that.

Actually I've just remembered what the potential problem is: what if
the error is only seen in the completion handler, not on submission?
I can imagine that it's only quite late in the day, after
usb_submit_urb has succeeded, that the problem is discovered (signaled
by the host controller perhaps) and the -EAGAIN is generated.  Then
we could end up submitting the urb again and again in a tight loop.
I'm not saying that this can happen, just that it is a logical
possibility.  Hmmm, I just had a quick look and it seems like
everything is fine.  Still, another possible way to organize things
would be to have two list heads, one for things ready to be sent (or
rx processed), one for things ready for re-use.



More information about the Usbatm mailing list