[Printing-architecture] Google Summer of Code 2014 - IPP-over-USB printer support - Joint project idea for OpenPrinting and the kernel

[Greg KH]

On Tue, Feb 25, 2014 at 08:56:23PM -0500, Michael Sweet wrote:
> Greg,
> 
> On Feb 25, 2014, at 8:47 PM, Greg KH <greg at kroah.com> wrote:
> > ...
> > So you want to do this as a userspace library talking directly to the
> > USB device through usbfs/libusb?  Or should the kernel provide a basic
> > "pipe-like" functionality to the hardware to make it easier for things
> > to be queued up to the device?
> 
> libusb is enough.
> 
> > Is there a pointer to the spec somewhere so that I can see what is
> > needed here?
> 
> http://www.usb.org/developers/devclass_docs

In reading the spec, it looks like some kernel code will have to be
written, as the default configuration for the printer device will cause
the usblp driver to bind to the device.  Are you thinking that libusb
will just unbind the printer driver and take over from there?  Why not
just use the kernel driver to expose another device node and have cups
talk to that?

thanks,

greg k-h