[ltp] ACPI S3 power drain: possible solution

[Volker Braun]

Hello everyone,

Please help us test the radeon powermanagement patch. This is supposed
to solve the "S3: high power consumption" bug detailed in
http://bugzilla.kernel.org/show_bug.cgi?id=3022

If you do not want to hunt down the individual patches from the
bugzilla entry, then there are two ways to test. First, if you happen
to use Fedora Core 3 on a thinkpad T4x series, then there are
precompiled kernel rpms. The following kernel has all the necessary
patches (and software-suspend-2) applied

http://carrot.hep.upenn.edu/~vbraun/kernel-T4x/test/kernel-DANGEROUS-T4x-2.6.11-8.i386.rpm

Install it, and run (as root) /usr/bin/thinkpad-T4x-suspend. This
script will suspend your computer and log the battery drain to
/var/log/battery.log. The "DANGEROUS" refers to the fact that this
kernel suspends the radeon chip to D2 sleep, and we are not sure
whether this works with all revisions of the hardware. 

If your computer hangs during resume, please try 

http://carrot.hep.upenn.edu/~vbraun/kernel-T4x/test/kernel-T4x-2.6.11-8.i386.rpm

This is almost the same kernel, but sends the radeon to D2 sleep only
on models where it is known to work. Now, you should definitely be
able to suspend/resume, but you may suffer of the battery drain bug
during sleep.

If you do not use Fedora Core 3 or have different hardware, you can
also compile a kernel yourself. First, get the vanilla 2.6.10 kernel
sources. Then apply

http://carrot.hep.upenn.edu/~vbraun/kernel-T4x/i386/patch-2.6.11-rc2-radeonfb-D2.patch.bz2

This patch unconditionally enables D2 sleep for the radeon chip. If
you have a T4x thinkpad, you can use my kernel config at

http://carrot.hep.upenn.edu/~vbraun/kernel-T4x/test/config

Then compile, install, and test. 

Please send the result (hang yes/no, battery drain yes/no) with the
precise model number (for example, I have a IBM thinkpad T41 2379-DJU)
to vbraun at physics dot upenn dot edu, it would be nice if your
subject line would include "RADEONFB:" to make sure that I do not miss
any emails.

Best,
Volker