Re: [linux-kernel] Re: [PATCH] x86: provide a DMI based port 0x80I/O delay override.

From: Zachary Amsden
Date: Thu Jan 10 2008 - 20:31:14 EST


On Wed, 2008-01-09 at 17:22 -0500, David P. Reed wrote:
> Zachary Amsden wrote:
> >
> > According to Phoenix Technologies book "System BIOS for IBM PCs,
> > Compatibles and EISA Computers, 2nd Edition", the I/O port list gives
> >
> > port 0080h R/W Extra page register (temporary storage)
> >
> > Despite looking, I've never seen it documented anywhere else, but I
> > believe it works on just about every PC platform. Except, apparently,
> > my laptop.
> >
> >
> >
> The port 80 problem was discovered by me, after months of "bisecting"
> the running code around a problem with hanging when using hwclock in
> 64-bit mode when ACPI is on. So it kills my laptop, too, and many
> currentlaptop motherboards designed by Quanta for HP and Compaq (dv6000,
> dv9000, tx1000, apparently)

Thanks very much for that - I was debugging this for a while too, and
eventually just shut off hwclock.

> Your laptop isn't an aberration. It's part of the new generation of
> evolved machines that take advantage of the capabilities of ACPI and
> SMBIOS and DMI standards that are becoming core parts of the market.

I beg to differ. I managed to turn the thing into a brick by upgrading
the BIOS (with the correct image, no less) in an attempt to fix it. I
just got it back from repair. I'm not sure that is positive
evolutionary development, but it certainly does make my laptop an
aberration :)

FWIW, I fixed the problem locally by recompiling, changing port 80 to
port 84 in io.h; works great, and doesn't conflict with any occupied
ports.

Zach

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