[feature request] Detect and filter power features in selection

[antis81]

A power feature should only be selectable/visible in the lxqt-powermanaget tool if the hardware/driver supports it.

Expected Behavior

Feature is not selectable/visible in GUI if hardware/driver doesn't support it.

Current Behavior

All features are selectable regardless of their availability.

Possible Solution

Seems implemented in lxqt-leave (via QDbus request?) - the hibernate button is "greyed out". If most/all features can be queried this way it would be great!

Steps to Reproduce (for bugs)

If possible - disable the feature under test. (For "hibernate" -> remove the resume HOOK in /etc/mkinitcpio.conf and reload/reboot).

Context

No action is taken on low battery after 30s timeout info box - battery management is correctly configured. Further investigation revealed that my setup has no hibernation feature. Selecting such feature in lxqt-powermanagement tool leads to no effect (silent error in the background) -> user confusion.

@tsujan FYI: Some time ago I disabled my swap partition (because SSD). Only a guess, but it makes sense hibernation would use that partition by default does it?

System Information

Not relevant here -> LXQt 0.17

[stefonarch]

I just checked my PC with swap partition, hibernation is not greyed out but fails, probably because no resume= parameter is set for the kernel.

lxqt-leave 
systemd: "CanSuspend" = "yes"
systemd: "CanHibernate" = "yes"

Debian (and probably ubuntu) do not use the kernel parameter but a config file for the ramdisk (have to look it up on my laptop), fedora no clue.
Ubuntu has probably still disabled hibernation by default as it often fails, depending on the hardware.
Hibernate can also usa a swapfile.

EDIT: Debian uses this (followed by a sudo update-initramfs -u)

$ cat /etc/initramfs-tools/conf.d/resume 
RESUME=UUID=f7d899f0-86dd-4b50-9a0c-10a818bb4d02

So just rely on systemd statements is probably non enough, checking for resume= parameters is required too.

[tsujan]

probably because no resume= parameter is set for the kernel

Yes, with Arch and its derivatives, resume=... is needed in /etc/default/grub and resume hook should be added to /etc/mkinitcpio.conf. Then, GRUB config and initramfs image should be regenerated and a reboot should be done.

So just rely on systemd statements is probably non enough

Probably. But the feature request is valid.

[tsujan]

If there's no reliable method for all distros, at least a warning can be added about hibernation somewhere, e.g. as a tooltip: "If you select hibernation, make sure that your system can really hibernate!"

[antis81]

@tsujan A reliable method requires a combination to check that ALL preconditions/crieria for hibernation are met. That is:

1. The interrupt listener is enabled (systemd or some common bus to query the flag).
2. The permanent storage (not a ramdisk!) is writable.

Now if hibernation is detected available (CanHIbernate=yes) I suggest to error out with a visual message when the write fails. This way it would guide the user to configure their system correectly for hibernation.

[tsujan]

@antis81
I'm certain that there are LXQt devs with the required know-how. It isn't my area of coding.

I try to make sure that valid bug reports and feature requests are open and invalid ones are closed. Our bug tracker needs to be organized; otherwise, it'll lose its functionality.

[antis81]

@tsujan No need to say mate! :)

[stefonarch]

In some way I think an if condition here could just remove the option if not available. Need to look into lxqt-leave.

[ comboBox->addItem(QObject::tr("Hibernate"), LXQt::Power::PowerHibernate);](

lxqt-powermanagement/config/helpers.cpp

Line 42 in eb61539

comboBox->addItem(QObject::tr("Hibernate"), LXQt::Power::PowerHibernate);

)