Re: VGA PCI IO port reservations

[Jeff Garzik <jgarzik@mandrakesoft.com>]

Russell King wrote:
> Jeff Garzik writes:
> > If XFree86 not fbdev is using the hardware, you can always have a stub
> > driver that does nothing but reserve the ports.  Remember, too, that the
> > ports claimed depend on register settings in the video card and PCI
> > config space..
> 
> I wish.  Unfortunately, ones of this nature tend to be rather fixed.  No amount
> of config space twiddling will move them.  However, as someone else pointed out,
> x86 gets around this problem by only allowing IO ports to be allocated in the
> (addr & 0x0300) == 0 range, thereby avoiding the problem.

Dig through the video card docs, even older ISA video cards let you
disable I/O decoding on all but a few ports, and/or relocate the ports
it does use to other areas.  Different with every video card, of course,
but most of them can do this to a greater or lesser extent.

	Jeff


-- 
Jeff Garzik             |
Building 1024           | The chief enemy of creativity is "good" sense
MandrakeSoft            |          -- Picasso
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/