On Saturday 12 January 2013 00:53:10 Xuetian Weng wrote: > > On Jan. 12, 2013, 12:18 a.m., Kai Uwe Broulik wrote: > > > plasma/generic/applets/batterymonitor/contents/code/logic.js, line 97 > > > <http://git.reviewboard.kde.org/r/108355/diff/2/?file=106715#file106715l > > > ine97>> > > > > But isn't it the dataengine that prematurely triggers a brightnes > > > change and OSD? When I restart plasma or use plasmaengineexplorer > > > and access the PM dataengine, the screen brightness changes and the > > > OSD appears. Shouldn't it be fixed inside the dataengine? > Restart Plasma shows OSD because you have battery plasmoid. > I don't see plasmaengineexplorer shows osd, unless you use setBrightness > service. > > The reason of this bug is, Slider have a value, when it's not equal to > current brightness, it will trigger valueChanged, and then trigger > brightnessChanged and send a call to dataengine service. If brightness > value is not changed from user operation on slider, it should never trigger > this call. > > If the fix in dataengine you mentioned is: > dataengine check the current brightness and argument of setBrightness > service is same or not, to decide whether to call powerdevil or not. > > I don't think it's the right approach, even if it can solve the problem. > Reason is, real brightness is saved on powerdevil side, which is a > different process. The value in dataengine is only cached value. If > setBrightness comes, there is no guarantee that this value is up-to-date > (even it's just theoretically possible), so if setBrightness comes, it's > always safe to send a real request to powerdevil. And the value send to > powerdevil will cause powerdevil to set current brightness is explicit set, > and do a lot of corresponding process, which should never be ignored just > because a cached value is the current value.
Please, backport the fix of the race condition to 4.9 and send an email to kde-packagers indicating that they should include this patch, it is quite nasty having an infinite loop of brightness change. Thanks. _______________________________________________ Plasma-devel mailing list Plasma-devel@kde.org https://mail.kde.org/mailman/listinfo/plasma-devel
