[sane-devel] Proposal: sanei_usb interface for USB scanners

[Henning Meier-Geinitz]

Hi,

On Sun, Aug 05, 2001 at 06:52:52PM -0600, Marcio Luis Teixeira wrote:
> I am particularly interested in knowing if your interface would
> be able to support for the PowerVision 8630 USB-to-parallel
> bridge. UMAX1220U and the HP4200 scanners both use this
> chip, and I imagine others do as well. Adrian Perez Jorge has
> written a very nice and sweet set of PV8630 interface file for
> his HP4200 backend. I have adapted these files for use in my
> own backend.
> 
> I have two questions for you: First, do you think it would be
> possible to adapt Jorge's PV8630 interface to use the sane USB
> interface you propose? I've posted the code here, if you need to
> look at it (it's very short):

If I understand correctly, the main problem is that you need control
messages. I'm not sure if this ioctl can be used for control messages
in general or if it's only useful for this chipset. At least in the
former case I don't see why something like 
sanei_usb_write_control (SANE_Int fd, SANE_Byte *data)
couldn't be added to sanei_usb. But I didn't look too closely at your
and scanner.c code.

> Second, I know the Linux kernel has some degree of support for
> USB scanners, through code written by David Nelson. These are the
> two files called "scanner.c" and "scanner.h". Is this what you meant
> by "the Linux USB scanner module"?

Yes.

> If so, that is good news, since
> the PV8630 interface code I mentioned above uses that already.

Because of the general discussion: Could you also use libusb instead
of the scanner module?

Bye,
  Henning