Worked in RELENG_5, fails in RELENG_6

[Nate Lawson]

John Baldwin wrote:
> 
> On Nov 29, 2005, at 10:50 PM, David Kelly wrote:
> 
>>
>> On Nov 29, 2005, at 5:10 PM, Alex Zbyslaw wrote:
>>
>>> David Kelly wrote:
>>>
>>>> Could I
>>>> boot a 5.4 CDROM to test ACPI?
>>>
>>> Yes you could.  I did this the other day on a machine that doesn't  
>>> even have a disk yet ;-)  acpidump is there.  Select fixit then  live 
>>> file system (if memory serves) but you probably knew that !
>>
>>
>> Problem solved, but I've been working on it too hard not to share  the 
>> story which might be useful:
>>
>> Without hw.physmem="2G" its now finding the full memory load so I  
>> don't know what was happening previously.
> 
> 
> Actually, this is the second report I've had that setting hw.physmem  
> interacts badly with ACPI.  The other report I had resulted in a  kernel 
> panic if it was set to 3G.

I suspect mapping the memory to read the FACS is failing for the 
hw.physmem case.  His machine probably has tables at 2G (highmem). A 
common location (other than < 1MB) is top of memory minus 16 MB.  I 
don't know what setting hw.physmem actually does -- does it change how 
we can map high memory?

-- 
Nate