[PATCH 0/2] ACPI: processor / EC enablement for core i7 platforms

Andy Whitcroft apw at canonical.com
Tue Jan 26 11:07:07 UTC 2010

On Fri, Jan 22, 2010 at 10:35:21PM -0800, Alex Chiang wrote:

> The first one is important: it will enable many new laptops with Intel
> Core i7 processors to idle much cooler and turns on TurboBoost. We
> discovered a common BIOS bug; lots of BIOS writers are specifying a C2
> latency greater than what Linux accepts (100us). As a result, Linux
> doesn't take advantage of the available C-states, idles much hotter, and
> rarely engages TurboBoost. Removing the check enables all that good
> stuff.
> Len told me on irc that he plans on marking it for -stable, but hasn't
> gotten around to it yet.

As we are getting more than regular (!) stable updates for .32 if its
going that route we will get it shortly I am sure.  But yes it looks
like the sort of thing we want.

> The second one is a little uglier. I discovered that some platforms need
> to evaluate the _PDC method before initializing the EC. This early
> evaluation loads some dynamic SSDTs and allows EC init to succeed.

If this is enabling broken platforms it would be nice to be able to get
this one via -stable too, to get it supported widly and it easier to
handle the longer-term stable tracking.  If not we are in more of a
position to take this one in Lucid as we are still in Alpha.

If you could let us know if the second patch is likely to be going to
-stable, and if a more minimal fix is likely.  Overall both enable pretty
common platforms and therefore interesting.


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