2.6.14 update throws kernel panic

[Wolfgang S. Rupprecht]

Sean Bruno <sean.bruno at dsl-only.net> writes:
> I have a dual opteron 246 with 6GB of ram on an ASUS K8N-DL.  It
> apparently doesn't have an IOMMU on board, so I have been able to
> function with the iommu=memaper=3 option up until now.
>
> The panic was pretty short, no code or pointer to output.  It just
> referenced the fact that I didn't have an IOMMU and halted.

Same thing here, but a different board -- tyan k8e w. 4G dram.  What I
did that seems to have fixed it was 1) updated to the latest bios.
That moved the "no iommu" panic early on instead of during the final
stages of booting. 2) Selected the "reset to optomized settings". 3)
changed a mystery bios setting from "non-linux OS" to "linux OS".

    bash-3.00$ cat /proc/mtrr 
    reg00: base=0x00000000 (   0MB), size=2048MB: write-back, count=1
    reg01: base=0x80000000 (2048MB), size=1024MB: write-back, count=1
    reg02: base=0xc0000000 (3072MB), size= 256MB: write-back, count=1
    reg03: base=0xd0000000 (3328MB), size= 128MB: write-back, count=1
    reg04: base=0xd7f00000 (3455MB), size=   1MB: uncachable, count=1
    reg05: base=0x100000000 (4096MB), size= 512MB: write-back, count=1
    reg06: base=0xd8000000 (3456MB), size= 128MB: write-combining, count=1

I seem to have most of my memory too.  (Not sure if the 128MB from
reg06 is my PCIe frame buffer or if it is real dram.)  If the former,
I'm still missing some 128MB of dram, but thats better than 4 months
ago when I was missing a whole 1GB of dram before playing with the
bios's MTRR settings.

I do wish the mobo vendors would spend a bit more effort documenting
what the various software settings do.  I would love to know what the
"linux os" switch setting does.

-wolfgang
-- 
Wolfgang S. Rupprecht                http://www.wsrcc.com/wolfgang/