bouyer@antioche.lip6.fr said:
> Well, this is another problem entirely, as the X servers are in
> userland. We would need a sysctl tree for this, but I'm not sure how
> to make this fit in the sysctl tree. 

While this is not relevant for the original question, I'd throw
in my opinion on the right way to do this:
The X server should get all the information it needs from the wsdisplay
device. This could be the pci config register contents, or it could
even provide the mmap() interface for all memory space ranges.
What the i386 X servers do currently - scanning the PCI bus from
userland - is dangerous because there are stateful transactions
which could be interrupted by a context switch.
Unfortunately, the structure of the xfree86 code makes this quite hard.

best regards
Matthias