Hi, Prompted by what seems to be a renewed focus on the org.freedesktop.ScreenSaver interface [1][2][3] I've noticed some problems with the KDE implementation, and have some ideas how to solve them:
* ScreenSaver inhibit does not imply powerdevil ChangeScreenSettings (i.e. DPMS) inhibit, and vice versa, * Neither inhibit implies powerdevil InterruptSession (i.e system suspend) inibit, * The Solid::PowerManagement::*SuppressingScreenPowerManagement functions only use the ScreenSaver.Inhibit interface if the powerdevil PolicyAgent interface is present. The first problem is partly obscured by the fact that some third-party ScreenSaver.Inhibit users also turn off DPMS directly - albeit in a way that doesn't work in gnome but currently does in KDE. It seems the pre-4.10 screensaver did check the DPMS status before activating but I'm not sure whether porting over that code is the right solution - it's not a complete solution anyway. This may also mean that ScreenSaver inhibit doesn't prevent powerdevil dimming the screen. The second problem is strictly correct as far as the powerdevil API goes, it's just not very useful[4] - although it's possible to argue that suspending the computer changes screen settings. I can't think of any use case for keeping the screen awake but still auto-suspending the computer after an idle timeout. And it's probably not what users of the ScreenSaver interface want. The third problem simply prevents applications using these functions working as intended in versions of gnome that support the ScreenSaver inhibit interface. So, I propose the following as minimal fixes, hopefully suitable for 4.10: * Have the ksmserver screenlocker pass ScreenSaver inhibits on to powerdevil via the PolicyAgent interface * Possibly have the ksmserver screenlocker check DPMS activation status before activating, although maybe not in a straight port of the krunner screensaver code * Change the powerdevil PolicyAgent to always have ChangeScreenSettings imply InterruptSession (as an alternative, have just the ScreenSaver and Solid::PowerManagement::beginSuppressingScreenPowerManagement use the InterruptSession flag - as I understand it, applications shouldn't be using the kde-namespaced dbus interfaces directly, is that correct?) * Have Solid::PowerManagement::*SuppressingScreenPowerManagement unconditionally call org.freedesktop.ScreenSaver. Further to this, is there any benefit to trying org.kde.Solid.PowerManagement.PolicyAgent first? I'm not sure whether there's any tricky ABI issues in changing the Solid::PowerManagement implementation? I'll have review requests for these proposals, hopefully in the next day or so. Thoughts? Oliver [1] https://bugzilla.gnome.org/show_bug.cgi?id=689225 [2] https://trac.videolan.org/vlc/ticket/7824 [3] https://bugzilla.mozilla.org/show_bug.cgi?id=811261 [4] Very briefly discussed at http://drfav.wordpress.com/2012/01/18/some-news-and-improvements-in-inhibition/#comment-2420 _______________________________________________ Plasma-devel mailing list Plasma-devel@kde.org https://mail.kde.org/mailman/listinfo/plasma-devel
