Re: cqcam-40b RPM
> Does anyone have a generic parallel port driver for Linux? I've written
> a FreeBSD loadable device driver which lets any user write to the output
> and control ports, and read from the status port, and I'm thinking something
> like this would come in handy for Linux as well. Cqcam would definitely
> benefit from it.
On the contrary, I would imagine that it could be quite a performance hit.
inb() and outb() are called hundreds of thousands of times per frame, and
they directly determine your frame rate. If they're asm instructions or
simple macros, that's fast. If each call requires several function calls
and context switches, that's not.
Either the entire driver (in cqcam that would be port.o and camera.o) or
nothing at all should be loaded into kernel space. I've kept cqcam
entirely in user space for a few pretty good reasons.
(An aside: the Solaris/x86 driver, if I write one, will require a kernel
module, because user space programs can't do inb/outb. Annoying.)
| Genius may have its | Patrick Reynolds <firstname.lastname@example.org> |
| limitations, but stupidity | Second-year UVA CS major .and. geek for hire |
| is not thus handicapped. | http://www.cs.virginia.edu/~patrick/ |
| --Elbert Hubbard | |