[Pm-utils] Some thoughts about some of the hooks

Richard Hughes hughsient at gmail.com
Tue Oct 10 09:18:31 PDT 2006

On Thu, 2006-10-05 at 18:50 +0200, Stefan Seyfried wrote:
> Hi,
> while investigating pm-utils, i went through all the hooks that are in the
> default distribution. This is what i found:
> 01grub:
> - should not be the first one that is called. If something fails and we do
>   not actually suspend, the user will have a surprise at the next reboot.
> - we need to restore the original behaviour in case the suspend fails.
> - should not be in the pm-utils package but in the grub package.

Yes, agree.

> 05led:
> - the kernel should actually do this when platform mode is used. It seems
>   to behave strangely since some versions, though, so i will investigate
>   this.

Last time somebody checked this was still needed, hwo do you mean
platform mode?

> 10NetworkManager
> - should be in NM package


> - shouldn't the "session daemons" actually do this? Send a "going to suspend"
>   signal which NM (and others) will listen to?

gnome-power-manager currently does this, but it NetworkManager doesn't
mind being asked twice.

> 20video:
> - should be the last thing that is done before suspend, so it will be the
>   first thing that runs after resume. Otherwise users that switch the console
>   too might cause trouble.

Yes, agree.

>   This is one reason why s2ram has everything in one binary, to make it less
>   likely that somebody else messes around with the video hardware. Still not
>   perfect (it should be in the kernel), but we might get it there with some
>   help from the uswsusp infrastructure (freeze everything but s2ram).


> 49bluetooth:
> - what is this good for? It is much easier (and safer) to just virtually
>   unplug the BT dongle before suspend (by rmmod'ing hci_usb) and replugging
>   it after resume. I never had a single problem with that.

Yes, although the kernel should probably be fixed to "just work".

> 50modules:
> - different lists of modules for suspend / hibernate might be a good idea
>   (yes, i had a machine with r8169 that needed to be unloaded before suspend
>   to RAM otherwise the machine would lock up hard, but needed to stay during
>   suspend to disk, otherwise the network was dead. The driver is fixed now.
>   :-)

Yes, I keep getting emails about how to blacklist oddball modules, so
this has to stay :-)

> 90clock:
> - setting the hwclock before suspend is only needed if your cmos clock runs
>   badly wrong. If you do not have ntpd running (no network, notebook), then
>   it might make things even worse. Resetting system time after resume from
>   the cmos clock is not needed, the kernel does this already.
>   (We had this option in powersaved since up to 2.6.7(?) the kernel did not
>   do this correctly. After the kernel was fixed, we set the default to "off".
>   I never had a bugreport about it ever since, so i wanted to remove it from
>   powersaved anyway).

I know nothing about this one. Peter?

> - just waiting 20 seconds does not ensure that NetworkManager etc. has come
>   back.
>   -> this should be done from a networkmanager-dispatcher-skript.
> - if it stays, it should be in the ntpd package
> 95led:
> - see 05led :-)
> This is what i saw after a short look. There might be stuff that i simply
> don't understand, but before i start adding more stuff to the hooks directory,
> i want to know if i am on the right track :-)

You are, nice one.


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