Bug#649540: ACPI failures on Dell Latitude E6220

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

fixed 649540 3.1.5-1
thanks

This issue appears to be worked around by

  linux-image-3.1.0-1-amd64 3.1.5-1

Note that it is *not* fixed by

  linux-image-3.2.0-rc4-amd64 3.2~rc4-1~experimental.1

The result is that idle time on battery *doubled*.  I'm now getting
4 hours idle time on the small (3 cell) battery, which is what I was
expecting when I bought this laptop.

In case you're interested in what's going on under the hood -- the
kernel is now able to put the processor in one of the low-power
"package" states.  Previously, the cores were able to switch to
low-power states, but the package remained in PC0.

 cr CPU    %c0  GHz  TSC    %c1    %c3    %c6    %c7  %pc2  %pc3  %pc6  %pc7
           1.03 0.80 2.49   5.21   0.01   0.00  93.74  1.22  0.00  2.07 84.59
   0   0   2.32 0.80 2.49   3.02   0.03   0.00  94.63  1.22  0.00  2.07 84.59
   0   2   1.05 0.80 2.49   4.28   0.03   0.00  94.64  1.22  0.00  2.07 84.59
   1   1   0.60 0.80 2.49   6.55   0.00   0.00  92.85  1.22  0.00  2.07 84.59
   1   3   0.14 0.80 2.49   7.01   0.00   0.00  92.85  1.22  0.00  2.07 84.59

-- Juliusz