Setting power management profile in Energy Saving does nothing

Hi all

In System Settings… Power Management… Energy Saving in KDE on Ubuntu 24.04, I’ve configured the power management profile for battery and AC modes. However, switching between battery and AC does not trigger an actual change between power management profiles.

Running Plasma 5.27.11

Thanks

what does

sudo strings /sys/firmware/acpi/tables/DSDT | grep -i 'windows ' | sort

show?

Microsoft Windows NT
Windows 2001
Windows 2001
Windows 2001.1
Windows 2001 SP1
Windows 2001 SP2
Windows 2006
Windows 2006
Windows 2009
Windows 2009
Windows 2009
Windows 2012
Windows 2012
Windows 2013
Windows 2013
Windows 2013
Windows 2015
Windows 2015
Windows 2017
Windows 2017
Windows 2017.2
Windows 2017.2
Windows 2018

so an older bios, then

i’ve had luck getting my older PC to have proper access to the acpi features of the motherboard by adding this kernel parameter to /etc/default/grub with latest windows supported by your m/b.

GRUB_CMDLINE_LINUX="acpi_osi=! \"acpi_osi=Windows 2018\" mem_sleep_default=deep reboot=bios"

be sure grub is updated after making any changes
sudo update-grub or whatever command your distro uses to update the grub boot files.

1 Like

I have no idea how you came across that command line, but it’s done the trick! Thanks so much for replying and for your help with this. Seems like the type of things distros should auto-detect and prepopulate themselves, rather than assuming people are running the latest and greatest…

newer bios don’t seem to have issues but depending on the motherboard they only offer up acpi features to the “detected” windows versions in their list.

so the command is letting linux pretend to be a windows OS in order to get at the features.

only reason i needed to learn this was because i had a nividia card.

my amd card does suspend/resume just fine without those params, i’m guessing it’s got something to do with the video drivers.