Arch Linux

digitalone

Member

Registered: 2011-08-19

Posts: 346

Is pm-utils really useful for suspension and hibernation?

Hi everyone. First of all, I'm italian, therefore sorry if my english is bad.

I have a Toshiba laptop with Arch Linux x64 and KDE.
I use laptop-mode-tools for power management, and, following what is described here:
combined with acpid, CPU frequency scaling, and pm-utils, LMT provides most users with a complete notebook power management suite.
I installed acpid, cpupower and pm-utils too.

Only in the last few days I found out that laptop-mode-tools and pm-utils go in conflict!
pm-utils has some scripts located in /usr/lib/pm-utils/power.d that overwrite laptop-mode configuration.
For these reason, I would never write laptop-mode-tools and pm-utils in the same sentence. Neither in wiki pages.

However, I disabled these scripts and now laptop-mode works perfectly.
But, I wonder: is pm-utils really useful for suspension and hibernation?

For example, I disabled brightness control in laptop-mode because it's useless. I can control brightness with KDE power management system. From user interface it's more comfortable.

If I uninstalled pm-utils, would suspension and hibernation work with KDE UI?
Thanks.

Raynman

Member

Registered: 2011-10-22

Posts: 1,539

Re: Is pm-utils really useful for suspension and hibernation?

From the pm-utils wiki page:

pm-utils is a collection of shell scripts that wrap the kernel mode suspend/resume with the various hacks. These hacks are needed to work around bugs in drivers and subsystems that are not yet aware of suspend. It is easily extensible by putting custom hooks into a directory, which can either be done by the system administrator or those hooks can be part of a package, especially if this package needs special attention during a system suspend or power state transition.
A lesser known feature is one that mimics toggling done by Laptop Mode Tools.

So if the kernel mode suspend/resume works for you, you can do without the scripts provided by pm-utils. However, it seems like you use KDE, and pm-utils is in the dependency tree for kdelibs, so removing it might not be a good idea.

The last sentence in the quote refers to the command pm-powersave and associated scripts in /usr/lib/pm-utils/power.d as you discovered. If you don't use that command, those scripts shouldn't be executed, but /usr/lib/pm-utils/sleep.d/00powersave executes pm-powersave during suspend/resume. So if you disable that script, you (or KDE) should be able to use the suspend/resume scripts without interfering with LTM.

elkoraco

Member

Registered: 2013-02-18

Posts: 140

Re: Is pm-utils really useful for suspension and hibernation?

The KDE power manager should use systemd for suspending and hibernating, so pm-utils are not necessarily needed, but they have some useful powersaving functions.

digitalone

Member

Registered: 2011-08-19

Posts: 346

Re: Is pm-utils really useful for suspension and hibernation?

However, it seems like you use KDE, and pm-utils is in the dependency tree for kdelibs, so removing it might not be a good idea.

You're right. I can't remove pm-utils, because it's a upower dependency, and upower is a kdelibs dependency.

The KDE power manager should use systemd for suspending and hibernating, so pm-utils are not necessarily needed,

No.

but they have some useful powersaving functions.

Not useful if you already have laptop-mode-tools.

Last edited by digitalone (2013-03-20 14:25:37)