Bug 466624

Summary:	Allow entering Power Save mode even when the hardware doesn't support Performance mode
Product:	[Plasma] plasmashell	Reporter:	Ilya Fedin <fedin-ilja2010>
Component:	Power and Battery widget	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	CONFIRMED ---
Severity:	wishlist	CC:	kde, natalie_clarius, nate
Priority:	NOR
Version First Reported In:	5.27.1
Target Milestone:	1.0
Platform:	NixOS
OS:	Linux
See Also:	https://bugs.kde.org/show_bug.cgi?id=467253
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Ilya Fedin 2023-02-28 22:35:59 UTC

SUMMARY
This driver exists for a reason: it allows applications to query system-wide energy saving mode even if there's no hardware support. Since Plasma ignores these profiles, it's not possible to set power-saver mode so applications consume less battery.


STEPS TO REPRODUCE
1. Have hardware without power-profiles-daemon special driver
2. Try to enable energy saving mode

OBSERVED RESULT
Plasma lets me to do so

EXPECTED RESULT
Plasma hides the option from the UI

SOFTWARE/OS VERSIONS
Operating System: NixOS 23.05
KDE Plasma Version: 5.27.1
KDE Frameworks Version: 5.103.0
Qt Version: 5.15.8
Kernel Version: 6.1.12-zen1 (64-bit)
Graphics Platform: Wayland
Processors: 8 × AMD Ryzen 5 3500U with Radeon Vega Mobile Gfx
Memory: 5.7 GiB of RAM
Graphics Processor: AMD Radeon Vega 8 Graphics

Comment 1 Ilya Fedin 2023-02-28 22:36:34 UTC

Oops, swap the observed and expected results

Comment 2 Natalie Clarius 2023-11-19 00:59:33 UTC

We recently thought about doing this, but the conclusion was that given the only thing that happens in this placeholder performance mode on the end of the power profiles daemon is a change in charge method with unclear effectiveness, it would seem like a false promise to expose this. If (as was the idea behind that mode) other software would use this information to do their own power saving measures, this would change matters.

Do you know of any applications that actually make use of this? 

Related: the idea of Plasma doing some power saving on its own: https://bugs.kde.org/show_bug.cgi?id=467253

Comment 3 Ilya Fedin 2023-11-19 01:05:52 UTC

I need that to debug the use of the API in an application I contibute to

Comment 4 Natalie Clarius 2023-11-19 01:19:05 UTC

Can you be more specific? Where does Plasma exposing the profiles enter the equation? Given that for the purposes of app development, you can just interact directly with the power profiles daemon service, the question here is whether there are enough apps that do anything with this information that it would be worth for Plasma to show a UI for the user to interact with the profiles.

Comment 5 Ilya Fedin 2023-11-19 01:25:13 UTC

I don't know any other than the one I contributed the implementation to - Telegram Desktop

Comment 6 Ilya Fedin 2023-11-20 15:13:05 UTC

Do i need to provide any other info?

Comment 7 Ilya Fedin 2023-11-20 15:18:28 UTC

I also think this is kind of chicken & egg problem. I wanted to test the UX a typical user would get but when I noticed no UI for the API in Plasma I thought it's not supposed to be used by applications like that. Fortunately I checked other DEs (GNOME) and found this behavior is specific only to Plasma. I guess various GNOME applications can use this API as well but as long as Plasma doesn't provide the UI to users, the Qt world just won't see a reason to use the API I guess by thinking there's no such feature just like you think right now that there's no one who would like to use it.