Re: Loading Pentium III microcode under Linux - catch 22!

["Chris Rankin" <rankincj@yahoo.com>]

 --- Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> As far as I am aware none of the microcode updates
> even apply to 933Mhz era PIII, just the ones the
> BIOS ships with by default nowdays. Also the kind of
> stuff the errata fix are obscure ultra-weird corner
> cases people just don't hit.

Lucky me, eh?

My CPUs *do* take microcode, and they are 933 MHz...
;-). I upgraded from a pair of 733 MHz CPUs bought in
July 2000, and my current BIOS just doesn't have any
microcode for them. Without the update, I used to come
back at the end of the day, switch on the KVM and be
unable to use the keyboard and mouse.

Anyway, I wasn't aware that Intel had released a
changelist for their microcode updates. Goodness knows
what bugs they're fixing.

> Thus I'd be very suprised if loading the microcode
> any earlier was neccessary - certainly nobody else
> has reported needing to.

My machine is currently hanging during boot-up (while
fscking the root partition, or releasing the "init"
memory), and CPU malfunction is the leading candidate
explanation. I have already replaced the 300W PSU with
a 400W one and tested the memory.

> > In an ideal world, I would like Linux to load the
> > microcode *before* the kernel boots, which begs
> > the question of "How?". Can you suggest anything,
> > please?
> 
> The kernel can't load the microcode until it has
> booted,

Yes, that's the "catch-22" bit. I was originally
thinking about either a bootstrapping floppy disk, or
maybe hacking some code into the boot-up sequence
itself.

> it can load it very early after that from initrd.

OK, I'll look into that.

Cheers,
Chris



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