Am Di., 22. Sept. 2026 um 14:05 Uhr schrieb Thomas Zimmermann <[email protected]>: > > The whole design here is to put the compositor in control. For > > example if compositor wants to enforce brightness to be a certain > > value when certain content is being displayed. > > And as I mentioned, it might not be that easy. Sysfs has been the entry > point to backlight brightness so far AFAIU. Yes, but this doesn't remove or break the sysfs API for old userspace, it just allows new userspace to handle things more properly.
> Did you consider treating this similar to display hotplugging? When the > user plug a display in or out, the DRM driver sends a message to the > compositor in user space. [1] I think it might be possible to do a > similar thing for changes to brightness. Notifying the compositor after the fact would not be ok. All the other display properties are under exclusive control of the process that holds drm master, backlight being different is one of the problems fixed by this new API. - Xaver
