Re: [PATCH] HPET: Drop WARN_ON for mismatch on HPET CMP readback

From: Andi Kleen
Date: Thu Feb 04 2010 - 14:32:32 EST


On Thu, Feb 04, 2010 at 11:22:15AM -0800, Pallipadi, Venkatesh wrote:
> On Thu, 2010-02-04 at 11:11 -0800, Andi Kleen wrote:
> > HPET: Drop WARN_ON for mismatch on HPET CMP readback
> >
> > At least one Intel chipset seems to always return a constant value
> > when reading back the HPET CMP register. This triggers the WARN_ON_ONCE
> > on each boot.
>
> I don't know of chipset returning a constant value. Which chipset is
> this one?

Ibex Peak. That is I'm not sure it's fully constant, but at least
it's always the same value on the HPET read triggering on boot.

>
> http://marc.info/?l=linux-kernel&m=125849385330302&w=2
>
> I wanted to send out final patch with a pointer to ICH9/10 spec update
> which describes the errata. But, look like that spec update hasn't
> happened yet. As we found issue with atleast one chipset with this
> warn_on, I would prefer retaining it, with a fix like above.

Ok fine for me. I only really care that the ugly backtrace
goes away.

-Andi

--
ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/