[sane-standard] "basic" scanning with usb canoscan?

[Henning Meier-Geinitz]

Hi,

On Thu, Aug 19, 2004 at 11:11:58AM -0700, Laurent Cocea wrote:
> [1] Why is it necessary to develop another driver (sane-backend) for the
> Canoscan D646U USB scanner to work with xsane if the scanner has already
> been detected by the kernel and the scanner module has been loaded? A
> similar step doesn't seem to be required for the USB webcam to work with
> Camorama.   

There is no standard for USB scanners. In fact, there is no standard
for scanners at all. As USB as well as SCSI are standards, it's easy
to "detect" the scanner (vendor/product ids or even names). But you
still have to write a driver for every single scanner chipset.

> [2] Is the scanner module loaded by the kernel sufficient for some
> "basic" scanning to be carried out in xsane with the Canoscan D646U?

No. The scanner module just detects scanners and provides endpoints to
write/read commands and data. It's not a real driver.

Bye,
  Henning