Re: Is it useful to support user level drivers

[john slee]

On Thu, Jun 21, 2001 at 06:38:09PM +0700, Dmitry A. Fedorov wrote:
> kernel module to delivery hardware interrupts to user space
> programs. Hardware interrupts (IRQ) are accessible by
> character devices /dev/irq[0-15]. Interrupts delivered by
> signals and select(2)/poll(2)

i believe libgpio uses the existing usb/iee1394/serial/parallel
interfaces to provide a limited userspace driver capability.  gphoto2
uses this to support a LOT of digital cameras entirely in userspace...

obviously this concept isn't covering everything but it sure covers a
lot of bases.  also depends on what you understand a "driver" to be...
from a "common user"'s perspective it just means "it makes my WinWidget
work!"

it's similar to what you describe above in that there's a kernel
interface, but it's more specific than /dev/irq5.  this is good in that
you don't want a different usb driver for every userspace usb device
driver...

http://sourceforge.net/projects/gphoto/ (i think)

j.

-- 
"Bobby, jiggle Grandpa's rat so it looks alive, please" -- gary larson