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[Libreboot-dev] enable C2E, C4E and dynamic L2 cache on model_6ex cpu

From: Arthur Heymans
Subject: [Libreboot-dev] enable C2E, C4E and dynamic L2 cache on model_6ex cpu
Date: Tue, 31 May 2016 20:59:37 +0200
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Attachment: 0001-Enable-extended-states-and-dynamic-L2-cache.patch
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I saw some TODO in the model_6ex code about extended deeper sleep (C4E)
and dynamic L2 cache. This is the code for core duo 32bit cpu found in
the x60, t60, macbook1,1. 
I just copied the msr bits from a later cpu in that code and it worked.

What this is supposed to do is force C2 in C2E and C4 in C4E. Those
are intel specific c-states that reduce the voltage more in the cpu.

For the idle power usage (C4) not much change.
For the C2 state it improves things a lot. C2 seems to consume a lot
of power (17-18W) and after this patch it went down to ~14W.
So depending on the workload power usage might improve a little.

This is measured using battery discharge rate which can be inaccurate.
Someone with a good power meter might be able to check differences more

Arthur Heymans

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