[sane-devel] [RFC] additional sanei_usb API to queue multiple URBs asynchronly

Gerhard Jaeger gerhard at gjaeger.de
Fri Mar 3 07:10:10 UTC 2006

On Thursday 02 March 2006 13:06, René Rebe wrote:
> Hi all - again,
> On Wednesday 01 March 2006 22:53, René Rebe wrote:
> > Hi all,
> > 
> > I currently review how to further improve the SANE/Avision backend to
> > get to the scanners maximal thruput, e.g. what the Windows driver
> > get's out of those devices.
> > 
> > The 16kB buffer of the Linux usbfs devio looks like a showstopper and
> > the kernel people indicate it is not likely to be removed / resolved easily or
> > soon.
> > 
> > Another option would be to queue more URBs and handle the completion
> > asynchonously. Would anyone veto when I further extend the API with
> > async flavours?
> Further investigation reviels just improving libusb to queue multiple URBs
> might be enough.
> Comments welcome,
Hi René,

FOA I'm curious about the transferrate you expect on your devices - guess
these are USB2.0 high-speed ones.
I currently could not estimate the impact on the backends I maintain, but
I think improving libusb ain't not a bad idea. Esp. when keeping in mind,
that newer devices provide higher resolutions and need the full cap
of USB2.0...

Keep us (me) informed about your progress - I'll test that even on my
slower devices.


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