Bug#696531: Power saving regression on Sandy Bridge

[Juliusz Chroboczek <jch@pps.jussieu.fr>]

>> On Dell Latitude E6220 (Sandy Bridge i5-2520M, integrated graphics),
>> power saving stops working after some time.  The symptoms are that idle
>> power consumption goes from 7W to 28W (!), and Powertop reports that PC7
>> is never entered.  A reliable way to reproduce it is to suspend the
>> laptop, but it sometimes happens spontaneously.

> I expect that
> we'll have to wait for a backported bug fix in the 3.7.y stable series.

It looks like it's fixed in linux-image-3.7-trunk-amd64 version
3.7.1-1~experimental.1 -- at least I couldn't reproduce it in five minutes'
testing.

(Now somebody is tweaking my cpufreq parameters whenver I unplug the cord,
but that's most probably a userspace issue, so not your problem.)

-- Juliusz