STEPS TO REPRODUCE 1. On a dell with oled screen 2. Lower brightness to 0 3. Raise brightness OBSERVED RESULT Screen turns black, and stays like that. Only workaround is to open and close laptop lid. EXPECTED RESULT Screen turn on to 5% brightness I tried with brightnessctl to raise it, but screen stayed black. I thought it was a generic Linux issue, but the issue occurs on both Kubuntu as ManjaroKDE. Ubuntu (gnome) works fine. I figured it was powerdevil as the moment it got to 0 brightness I got this message: dec 24 16:13:19 hostname dbus-daemon[756]: [system] Activating service name='org.kde.powerdevil.backlighthelper' requested by ':1.52' (uid=0 pid=1669 comm="/usr/lib/org_kde_powerdevil ") (using servicehelper) dec 24 16:13:19 hostname dbus-daemon[756]: [system] Successfully activated service 'org.kde.powerdevil.backlighthelper' SOFTWARE/OS VERSIONS Linux/KDE Plasma (Manjaro and Kubuntu) KDE Plasma Version: 5.23.4 KDE Frameworks Version: 5.88 Qt Version: 5.15.2 ADDITIONAL INFORMATION I set the severity to grave as this sometimes happen without toggling brightness, but with also regular power management.
I forgot to add, I'm on linux-5.16.0.1 so all oled patches are included already.
I could reproduce the issue in GNOME as well using brightnessctl s 0, nevertheless, perhaps a fix could be implemented to avoid going to 0 for specific type of screen.
> perhaps a fix could be implemented to avoid going to 0 for specific type of screen. Indeed. The place for that would be either upower or the kernel. If level 0 is destructive for this screen, it should be disabled for everyone.
For reference: https://gitlab.freedesktop.org/drm/intel/-/issues/4949 https://bugzilla.kernel.org/show_bug.cgi?id=215417
Still wondering though if there couldn't/shouldn't be something done from the KDE side. After some reading I see that there are quite some discussions between DE what the minimum brightness should be. On my laptop in GNOME this is 5. In case of my laptop the screen is actually turned off, which could be desirable if you could actually turn it on again :). Perhaps a configuration for powerdevil could be implemented that allows setting a minimum brightness?
Maybe you're right. I'm not sure how much of a use case there is for going to 0 brightness even for non-OLED screens. Typically that disables the backlight, but what's the point of that? You can't see anything with the backlight off, even in full sunlight. And we don't even let you do it using the slider in the applet anyway, so the slider is inconsistent with the global keyboard brightness shortcuts. Might be worth making 1 the lower bound, not 0. Kai, do you remember why we don't already do this, and are there any significant negative consequences I might be missing if we do it?
(In reply to Nate Graham from comment #6) > Maybe you're right. I'm not sure how much of a use case there is for going > to 0 brightness even for non-OLED screens. Typically that disables the > backlight, but what's the point of that? You can't see anything with the > backlight off, even in full sunlight. And we don't even let you do it using > the slider in the applet anyway, so the slider is inconsistent with the > global keyboard brightness shortcuts. > > Might be worth making 1 the lower bound, not 0. > > Kai, do you remember why we don't already do this, and are there any > significant negative consequences I might be missing if we do it? Just giving my two cents, I believe setting it to 1 would be a nice compromise. I noticed on every laptop I've ever used that Linux usually makes the screen go much darker than Windows, even on LCDs. While being able to get the screen very dim is a nice thing, it means Windows is probably limiting the minimum brightness too. From my experience, it looks like it's limited to 5% on Windows (which I think is not dark enough in some situations). 1% is probably dark enough for any kind of screen, including LCDs and OLEDs, and would probably avoid any problems with other screen technologies in the future.
*** Bug 454855 has been marked as a duplicate of this bug. ***
(In reply to guimarcalsilva from comment #7) Is there any way that I can edit a config file or something similar to get this minimum value to 1 instead of 0?
This was just fixed upstream in the Intel graphics drivers! See https://gitlab.freedesktop.org/drm/intel/-/issues/3657.
*** Bug 462140 has been marked as a duplicate of this bug. ***
Hey, so I've got a fresh install of KDE Neon on an LG Gram, and I'm still having this problem. I guess that upstream resolution hasn't made it's way to me? ``` OS: KDE neon 5.27 x86_64 Host: 17ZB90R-K.AAC7U1 0.1 Kernel: 6.2.0-31-generic DE: Plasma 5.27.7 WM: KWin CPU: 13th Gen Intel i7-1360P (16) @ 5.000GHz GPU: Intel Device a7a0 ```
Sorry, to be clear, I'm not having the original problem. My screen does turn back on after setting the brightness to 0. But I would like the brightness keys to not set the brightness below 1. The slider in the system tray bottoms out at 1, is there a way I can get the same behavior for the brightness keys?
That separate issue is already fixed for Plasma 6; see Bug 430439.