PCI ROM resource allocation issue with 2.6.17-rc2

[Matthew Reppert <arashi@sacredchao.net>]

I've been running 2.6.12-rc2-mm3 for a long time.  Recently I upgraded
a bunch of OS packages (Debian unstable), so I thought I may as well
upgrade the kernel, too.  I've got a dual-head setup driven by a Radeon
9200 and a Radeon 7000.  When I booted 2.6.17-rc2, X never came up; I
got "RADEON: Cannot read V_BIOS" and "RADEON: VIdeo BIOS not detected
in PCI space!" for the RADEON 7000, and it eventually gets in a loop of
spitting out "RADEON: Idle timed out, resetting engine ... " messages
in Xorg.log.  Doing a diff of working and broken logs uncovered that the
Radeon 7000's PCI ROM resource area had moved from ff8c000 to c6900000.
Once I removed the Radeon 7000 screen from the Xorg config, X came up fine
on the one head.  Adding stupid amounts of printks to the PCI subsystem in
.17-rc2 uncovered that at some point, the ROM area is discovered to be
at ff8c0000, but is later reallocated to c6900000.

I've also got a Promise PDC20268 whose expansion ROM seems to have made a
similar move (from ff8f8000 to c6920000), but the ATA devices attached to
that controller seem to work fine under 2.6.17-rc2.

I have a copy of relevant dmesg and lspci output, as well as a copy of
Xorg.log files, at http://sacredchao.net/~arashi/pci-problem/ .  I'll
try to binary-search for the last version of the kernel that works later
this week (hopefully by Tuesday afternoon), I just haven't had time to
since I've discovered the problem.

Matt