[sane-devel] sequence usb commands send, receive

Gerard Klaver gerard at gkall.hobby.nl
Sun May 7 18:35:37 UTC 2006


On Sun, 2006-05-07 at 20:10 +0200, Henning Meier-Geinitz wrote:
> Hi,
> 
> On 2006-04-29 13:55, gerard klaver wrote:
> > I have a question about usb commands.
> > I have for example the following sequence:
> > 
> > send urb 5, send urb 6, send/receive urb7, send/receive urb8, receive
> > urb 5, receive urb6
> > 
> > At this moment i don't know how te handle this.
> > send urb 5, 6 no problem, send/receive urb 7, 8 no problem, but how to
> > handle to receive urb 5 and 6?.
> 
> As far as I know, at least the stable libusb doesn't provide support
> for async io. Even if it did, I'm not sure if it would work with
> "Out-of-order" URBs. IIRC, this didn't work with SCSI either?
> 
> Does your USB device really depend on this order?
> 
> Bye,
>   Henning
> 
My authentec AES2501 fingerprint sensor usb sniff file shows that
sequence. 
One reaction i got, was that maybe the usb sniff output sequence is not
always correct, but just using urb 5, 6, 7, 8 didn't work either.
So i have to figure out, how to solve this.

-- 
--------
m.vr.gr.
Gerard Klaver




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