Subject: Re: [linux-pm] release early... powermac g5 suspend to disk

From: Johannes Berg <[email-masked]>
Date: Thu, 29 Jun 2006 18:24:00 +0200

Hi,

> Congratulations! Hehe, you have nice testcase for xfs now :-).

Yeah, already posted to xfs list ;)

> [ext2 is the filesystem you proably want to use while hacking such code]. 

Mounting read-only hasn't wrecked it any further so far :) And I was too
lazy to install a second system... Should've, I guess, hd is large
enough anyway.

> > Half of the time I'll be told by the softlockup watchdog that it locked
> > up, but sometimes it actually works, that is, it suspends and resumes.

Obviously that was phrased wrongly -- the code hangs and the softlockup
watchdog indicates it. But I don't know why. Can writing the MSR hang?

> I believe this is gone in -git kernels for some other reasons.

I'm not even sure the hack I did there with marking the area as nosave
is good. At the very least the code shouldn't live in the MPIC file
since the code reserving the chunk doesn't either.

What about the page_is_ram() part? Doesn't any other platform have a RAM
hole between 2 and 4 GB? Or is that handled more generically with
discontig support? (and if yes, how does discontig support work?)

johannes