[sane-devel] Concurrent USB scan acquisition

Henning Meier-Geinitz henning@meier-geinitz.de
Thu, 23 Jan 2003 10:55:17 +0100


On Wed, Jan 22, 2003 at 11:05:09AM -0800, Derek Chiles wrote:
> This is not really a development question

Despite its name, sane-devel is for all questions/discussion related
to SANE, not only development.

> but this seems like a good 
> place to ask it nonetheless. I'm interested in attaching many USB 
> scanners (of the same type) to one host and having them all scan 
> concurrently. I have a few questions about this:
> o Can it be done with the current USB driver?

The USB scanner driver in Linux 2.4.* supports upto 16 devices. In
2.5.* you should be able to use upto 256 scanners with devfs, but I
haven't tested that :-)

If you use libusb instead of the scanner driver, the number of
scanners is only limited by the restrictions of the USB.

> o If so, is this something sane could support or will I need to come up 
> with a custom solution?

SANE is limited to 100 simultaneous USB scanners currently. If this
isn't enough, you can increase this value in source code.

Scanning with five different scanners at the same time does work here.

Most of the backends support more than one scanner (at least gt68xx,
mustek_usb, epson, I don't know about the others), so to be sure, you'd
better tell us which scanners you would like to use.

Use the latest SANE and scanner driver versions for faster detection
of the scanners.