Re: no self-refresh during S3 - any debug hints?

[Len Brown <lenb@kernel.org>]

On Sat, 31 May 2008, Jeff Trull wrote:

> I made a breakthrough in my s2r debugging last night when I realized
> that the sooner I pressed the power button after suspend, the more
> life the system exhibited post-resume.  In fact when I attempted to
> resume immediately after entering suspend, my system had a successful
> resume from memory for the first time ever.  Therefore, I have a new
> hypothesis: DRAM self-refresh mode is not being properly entered.
> 
> I'm running kernel 2.6.20 on a laptop with an ATI IGP 320M Northbridge
> and an Athlon XP.  DSDT has a _PTS but no _GTS.  I'm comfortable
> recompiling the kernel.  Any suggestions as to how to proceed,
> experiments to run, etc.?

Start by running the upstrteam kernel -- now 2.6.26, just out of 
principle.

Then, see Documentation/power/basic-pm-debugging.txt

and try the options in /sys/power/pm_test

If the cause is as you suspect, they should all work.
If any of them fail, then there is a problem elsewhere.

eg. the deepest test is core:

# echo core > /sys/power/pm_test
# echo mem > /sys/power/state

should work, because it does everything except actually leap into
the BIOS to enter self-refresh.

# echo none > /sys/power/pm_test

then disalbes this test mode.

-Len