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SubjectRe: VGA PCI IO port reservations
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
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