Re: Suspend to RAM regression tracked down

[Jeremy Fitzhardinge <jeremy@goop.org>]

Jean-Marc Valin wrote:
> A while ago, I reported a suspend to RAM regression (fail to resume). I
> have since then tracked down the regression to the changes between
> 2.6.12-rc5-git5 and 2.6.12-rc5-git6. On my laptop, I have only been able
> to reproduce the problem with the ondemand cpufreq governor, but I've
> head of another user with the same (Dell D600) laptop having problem
> with the userspace governor as well. All the details are actually
> http://bugzilla.kernel.org/show_bug.cgi?id=6166 but it seems like it's
> being ignored. It's currently assigned to the ACPI category, but maybe
> it belongs to cpufreq? Anyone can help here?
>   

There was a race in ondemand and conservative which made them lock up on 
resume (possibly only on SMP systems though).  There's a patch for that 
in current -mm, but I suspect there's another problem (still haven't had 
any time to track it down).

The workaround is to switch to one of the performance/powersave/user 
governors just before suspend, and restore the governor on resume.

    J