CPUTYPE?=athlon-xp breaks loader (was Re: instant reboot when trying to load recent RELENG_5 kernel)

[John Baldwin]

On Monday 01 November 2004 10:02 pm, Doug White wrote:
> On Mon, 1 Nov 2004, John Baldwin wrote:
> > Your BIOS writer needs to be beaten with a blunt instrument.  They are
> > trying to enter protected mode themselves and not handling the fact that
> > they can be called from vm86 mode.  There's not much FreeBSD can do about
> > narrow-minded, kludgey BIOS code.
>
> ISTR that some BIOSen try to play this game because they are trying to see
> if UDMA works.  Try demoting the disk to PIO in the BIOS; FreBSD ignores
> this setting when configuring disks, so its safe to leave that way.

That code in the Compaq/HP boxes is smarter, it doesn't unconditionally go 
into protected mode.  This sounds like the USB code in this BIOS is just 
buggy and is probably using protected mode to access the PCI config registers 
instead of using int 15h, function 87h like well-behaved BIOS writers do.

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org