[sane-devel] Learning about USB and scanners

[Henning Meier-Geinitz]

Hi,

On 2006-01-02 19:54, Stephen More wrote:
> On 1/2/06, Henning Meier-Geinitz <henning at meier-geinitz.de> wrote:
> 
> > Which scanner exactly?
> 
> Visioneer OneTouch 7600 USB

Shouldn't it be possible to use the existing viceo backend at least to
understand what's send to the scanner? That backend claims to support
that scanner.

> Ahh ! I think this leads to a bug in :
> http://protu.it.helsinki.fi/~lindi/usb/usbsnoop2libusb.pl

Was it you who entered this bug/wishlist report?
https://alioth.debian.org/tracker/index.php?func=detail&aid=302812&group_id=30186&atid=410366

In this case, could you provide a description or documentation for
this script?

On the other hand, if it has such grave bugs it may be better not to
link to it.

> I guess OUT OUT should be usb_bulk_write and OUT IN should be usb_bulk_read

Yes. These are URBs, not the actual physical data on the USB. That
means that the data is just read and not that a buffer filled with
zeros is sent to the scanner.

Also, you can tell if its a read or write by looking at the endpoint
number (if bit 7 is set (0x80), it's an IN endpoint).

Bye,
  Henning