Re: PATCH: Assume PM Timer to be reliable on broken board/BIOS

From: Olivier Fourdan
Date: Wed Jul 27 2005 - 00:33:20 EST

On Tue, 2005-07-26 at 17:34 -0600, Robert Hancock wrote:
> > In a nutshell, sometimes, the PIT/TSC timer runs 3x too fast [1]. That
> > causes many issues, including DMA errors, MCE, and clock running way too
> > fast (making the laptop unusable for any software development). So far,
> > no BIOS update was able to fix the issue for me.
> Shouldn't this be looked into further rather than adding this
> workaround? Surely Windows is using the PIT as well, so there must be
> some way to get it to behave properly..

Surely, but I've been desesperatly trying to find the cause w/out
success for months.

My first idea was that the BIOS doesn't set the CPU voltage properly at
boot, so I made up a patch that sets the right fid/vid before any
calibration but that didn't help.

The BIOS is wrong (ie the BIOS reports a 1/3 of the actual CPU speed),
memtest86+ which doesn't use any ACPI or whatever reports wrong time
too, so it's definitely not a Linux bug.

My guess is that Windows reinitialize some register but it's hard to


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