Re: AMD X2 unsynced TSC fix?

Vojtech Pavlik
2006-10-28T19:59:12Z

On Sat, Oct 28, 2006 at 02:22:11PM -0400, Lee Revell wrote:

> On Fri, 2006-10-27 at 20:59 -0700, Andi Kleen wrote:
> > > Fortunately, we usually have an HPET, these days. You can
> > definitely
> > > resync and get near-linear values of RDTSC.
> >
> > No we don't -- most BIOS still don't give us the HPET table
> > even when it is there in hardware. In the future this will change sure
> > but people will still run a lot of older motherboards.
>
> I have exactly such a system (see thread "x86-64 with nvidia MCP51
> chipset: kernel does not find HPET"). Is there anything at all I can do
> to make the kernel see the HPET? Can I try to guess the address? BIOS
> upgrade?

In most cases where the HPET is present but not reported, it's not
configured. Usually, you need to write a chipset-specific register to
configure the address.

Finding the register, finding some free MMIO space, writing the address
to the register and telling the address to the kernel is enough.

--
Vojtech Pavlik
Director SuSE Labs