SUMMARY Thinkpad T480 (intel only) with one HDMI external monitor and one display port monitor. On AC. STEPS TO REPRODUCE 1. In settings Power Management 'AC' set a time for Screen Energy Saving. e.g. Switch off after 1 min 2. Leave computer inactive 3. OBSERVED RESULT Laptop display panels powers down (backlight off): good But two external monitors stay on EXPECTED RESULT All three monitors should power off. note that these monitors do power off with manual xset such as xset dpms 300 360 360; xset +dpms and the poweroff when the laptop sleeps (laptop Suspend session: After xx min Sleep works perfectly) so there is no hardware problem SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: (available in About System) KDE Plasma Version: KDE Frameworks Version: Qt Version: Operating System: KDE neon 5.16 KDE Plasma Version: 5.16.4 KDE Frameworks Version: 5.60.0 Qt Version: 5.12.3 Kernel Version: 5.0.0-25-generic OS Type: 64-bit Processors: 8 × Intel® Core™ i7-8550U CPU @ 1.80GHz Memory: 31.2 GiB of RAM ADDITIONAL INFORMATION
Note: the Button events handling option "Even when an external monitor is connected" is related to the problem. I normally have it cleared, so that I can close the laptop lid when working at my desk. But if I select this option, then the Screen Energy Saving timeout DOES poweroff all three monitors. I do not think this behaviour is expected. The layout of the "Even when an external monitor is connected" checkbox is nested under Button events handling, so it does not appear to be related to the Screen Energy Saving setting. I agree with the layout: suspend or merely turn off laptop display when the lid is closed is independent of screen energy saving. The "Even when an external monitor is connected" checkbox should not affect the Screen Energy Saving setting in my opinion.
> But if I select this option, then the Screen Energy Saving timeout DOES poweroff all three monitors. That's unusual and unexpected. That option should really only affect button presses, not the automatic timeout. But maybe that is the root cause for all of the "only one of my screens turns off" bugs I have seen. Maybe we're on to something! I'll have a look.
While I definitely observed the behaviour in my comment (only one screen powerered off), I tested it again today, first then "Even when external monitor is connected" checked. As expected, all monitors turned off. I think cleared the button, and repeated (I definitely Applied the setting change) but all monitors again turned off.
I think I may have confused myself about something.The automatic dim option actually fades the display backlight to completely off. This may give the illusion that only one display is being powered off.
(continued: because the only backlight that my computer can control is the laptop's own backlight, not the backlights of the two external monitors, hence 'dim' only takes effect on the laptop panel. Dim should problem do something more macos-like, and dim backlight to a non-zero setting.)
So, are you using the "dim" option, which only *dims* the screen in few steps, or the "off" option which puts the screen into standby mode? It cannot adjust the brightness of external monitors.
Created attachment 122074 [details] attachment-22832-0.html I have both set On Mon, 12 Aug. 2019, 16:51 Kai Uwe Broulik, <bugzilla_noreply@kde.org> wrote: > https://bugs.kde.org/show_bug.cgi?id=410799 > > --- Comment #6 from Kai Uwe Broulik <kde@privat.broulik.de> --- > So, are you using the "dim" option, which only *dims* the screen in few > steps, > or the "off" option which puts the screen into standby mode? It cannot > adjust > the brightness of external monitors. > > -- > You are receiving this mail because: > You reported the bug.
Created attachment 122075 [details] attachment-22906-0.html My point was that perhaps when I saw the laptop display go off and not the other screens, I thought the 'turn off' feature wasnt working, when in fact none of the screens turned off, instead the laptop screen dimmed so completely I came to the wrong conclusion. On Mon, 12 Aug. 2019, 17:45 Tim Richardson, <tim@growthpath.com.au> wrote: > I have both set > > On Mon, 12 Aug. 2019, 16:51 Kai Uwe Broulik, <bugzilla_noreply@kde.org> > wrote: > >> https://bugs.kde.org/show_bug.cgi?id=410799 >> >> --- Comment #6 from Kai Uwe Broulik <kde@privat.broulik.de> --- >> So, are you using the "dim" option, which only *dims* the screen in few >> steps, >> or the "off" option which puts the screen into standby mode? It cannot >> adjust >> the brightness of external monitors. >> >> -- >> You are receiving this mail because: >> You reported the bug. > >