On 3/6/2024 11:08, Xaver Hugl wrote:
Like already mentioned in the power profiles daemon repository, I don't think this makes sense. This is a display setting, which compositors have interest in controlling, for example to: - disable it in a bright environment, because afaiu it reduces the maximum screen brightness - disable it when it shows color critical content - disable it while profiling the display - enable it when it shows content that's definitely not color critical (based on the content-type property of Wayland surfaces) - enable it as a first step before properly dimming the screen on idle
This specific topic is on the agenda to discuss at 2024 Display Next Hackfest.
If the primary concern here is that this hasn't been used by compositors and potential power savings aren't being realized, that could be solved by providing documentation about what the feature does in the kernel, and by sending a mail to wayland-devel describing why it should be used. If the goal is to implement it in power profiles daemon and not get conflicts, I think disabling the property by default and instead enable it + disable the sysfs file when a CAP for it is set would make more sense than making the listed features impossible.
So the idea being if the compositor isn't using it we let power-profiles-daemon (or any other software) take control via sysfs and if the compositor does want to control it then it then it writes a DRM cap and we destroy the sysfs file?
