HEAD panic with ofw_pcibus.c 1.21 on Blade 100

[Nathan Whitehorn]

Gavin Atkinson wrote:
> On Mon, 2008-09-01 at 18:18 +0200, Marius Strobl wrote:
>> On Mon, Sep 01, 2008 at 03:20:27PM +0100, Gavin Atkinson wrote:
>>> Hi all,
>>>
>>> My Blade 100 now panics on boot with HEAD, and I've tracked it down to
>>> sys/sparc64/pci/ofw_pcibus.c 1.21 (SVN r182108) by marius at .
> 
>> The most likely reason for this is a buggy driver. In this
>> case the culprit appears to be the ISA front-end of ahc(4),
>> which assumes that it can do bus space reads and writes at
>> addresses that may in fact be assigned to a non-ahc(4)-
>> compatible device or none at all. While writing something
>> at an address that may no belong to the expected device
>> probably is a bad idea in generally, reading to and writing
>> from unassigned addresses may also trigger exceptions on
>> sparc64. I'm unsure how to really fix ahc(4) regarding this,
>> I think it should be okay though to only do it on i386 where
>> the address range in question probably is reserved for such
>> purposes (and which also is the only architecture FreeBSD
>> currently runs on where a machine might have an ISA-slot
>> and thus can use that front-end at all).
>> Justin, do you approve the below patch?

Speaking of ahc(4), I have one in my Ultra 5 which will not work unless 
I have options AHC_ALLOW_MEMIO in my kernel config. I think this option 
should always be valid for sparc64 systems. Can it be in the default kernel?
-Nathan