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Re: [Xen-devel] [patch] make cpufreq with speedstep-centrino work underX

To: Ian Pratt <m+Ian.Pratt@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] [patch] make cpufreq with speedstep-centrino work underXen
From: Christian Krafft <parabelboi@xxxxxxxxxxxxxxx>
Date: Tue, 18 Apr 2006 10:34:54 +0200
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Ian Pratt wrote:

The attached patch fixes the speedstep-centrino driver, to use the hypervisors MSR's instead of direct MSR access. Without the patch the frequency seems to have changed, but the powerconsumption of the CPU has not. Thanks to the patch of Matt T. Yourst found here http://lists.xensource.com/archives/html/xen-devel/2006-03/msg
It was easy to fix the centrino driver, too.

If someone could review the patch and bring it upsream (if it's ok), it would be very nice.

Why not just update xen's MSR emulation code to handle this case? The
msr hypercall is pretty much a legacy thing.


Hi Ian,

that sounds even better, no need to change all the other cpufreq drivers ;-)
Unfortunately I don't know how to fix the MSR emulation code.
Any idea, how much effort it will be, resp. when the fix might be available ?


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