laptop-mode disabled in kernel?

marc gmane at auxbuss.com
Tue Jul 11 23:44:44 UTC 2006


James Gray said...
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> marc wrote:
> > James Gray said...
> >> marc wrote:
> >>> In Dapper, my laptop fan never turns off after the first few minutes. It 
> >>> is always on. Whereas, in Windows, it rarely comes on. I'm pretty sure 
> >>> that this is because the disk never spins down.
> >> - -->8-- Snipped --8<--
> >>
> >>> Back to the disk. There's only one active ext3 partition plus swap - all 
> >>> other partitions are noauto. I've tried noatime and commit=600, but to 
> >>> noavail. Any ideas?
> >> ext3 is the problem with your disk.  It uses a forced-flush interval of
> >> about 30 sec IIRC.  In other words, regardless of what is or isn't going
> >> on, the ext3 driver forces a sync and hence the hard drive never goes to
> >> sleep (neither would you if someone poked you in the ribs every 30
> >> seconds!).
> >>
> >> Solution, unfortunately, requires reformatting ALL the ext3 partitions
> >> with something else.  I'd suggest reiserfs as, like ext3, is a
> >> journaling file system and is quite mature.  I can't remember if jfs and
> >> xfs use the same "fixed sync interval" fru-fru like ext3 though, so I'll
> >> hold short of recommending them.
> > 
> > Thanks for this. I was in two minds about going this way, but then 
> > decided to jump.
> > 
> > And now, I have a little problem :-o
> > 
> > Here's the story, so far
> > 
> > - moved Kubuntu (on sda3) to a safe place while booted on another 
> > partition (sda6)
> > - formatted sda3 as reiserfs
> > - amended both fstabs (sda3 and sda6)
> > - mounted the newly formatted partition
> > - moved the data back onto sda3
> > - rebooted.
> > 
> > Grub currently loads from sda3, or rather it doesn't now. I'm getting an 
> > error 17 : Cannot mount selected partition. I'm not overly surprised, 
> > but I'm not sure what to do next.
> 
> You probably need to add the reiserfs module to the initrd.  Add the
> reiserfs line to /etc/modules then rebuild the initial ram disk
> (mkinitrd), then move the old one out of the way, and copy the new one
> in (with the same name as the old one).  Reboot and you should be sweet.

Cool. I'll check. I'm finished with kernel building these days, but if 
it's just an initrd, then that's no big deal, and it can easily be 
reused.
 
> FWIW, I usually create a 30-50MB partition in ext2 format mounted at
> /boot - this avoids some problems with different boot loaders.  Maybe
> those problems are historical but it's been a practise that works well
> for me.

Yup, I know, and maybe I should, but I'm on a bit of a crusade to get 
Linux into the real world, and all this "olde worlde" Linux stuff is 
precisely what I'm avoiding. It's hard enough to get folk to look at 
Linux without the overheads ;-)
 
> > I can mount the partition from a live CD without a problem, and I 
> > obviously mounted it from my sda6 partition.
> 
> Yup - because the live CD loads the reiserfs module on demand as the
> kernel is already running and has mounted the /lib.  The problem with
> booting is that it needs the reiserfs module to mount "/", but the
> module is on "/"...chicken and egg problem.

Yup, been there with SATA drives last year... then before that... and 
before that... ;-) Time to Ubuntuise!
 
> Initial ram disks (initrd) were invented to get around this problem.
> Usually when you install Ubuntu (and any other Linux distro) the
> installer adds whatever modules that are needed to mount the root file
> system for you.

Indeed.

> If you change the format of the root file system
> post-installation, you need to modify the initial ram disk yourself.

Yup, it's a fair call.

Thanks a lot for the heads up. I'll give it a whirl towards the weekend 
when I have some time to get it sorted.

-- 
Best,
Marc





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