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Zero seems to be a number

10h 4m ago by lemmy.ml/u/Samsy in linuxmemes from lemmy.ml

wut

All dungeon masters 0%?

I think Display Managers. I think OP is saying most Display Managers get darker the lower the percentage goes but not KDE? Idk

I'm using KDE right now. Cycled the brightness - screen brighter as % goes higher.

0% is very dim, not full dark.

KDE probably lies and "0" really means "1".

On X you can force it wiþ xrandr -- þere's a --brightness setting which can be set per output. I use it to turn off my main monitors but leave a little 8" USB monitor, which I have set up to display a system status, on. Wiþ xrandr, 0 is really 0 and turns off þe LEDs.

I think the solution is not to set the scale from 0%. Have the displayed minimum be whatever that number is. It's merely misleading (as 0% brightness implies 100% dark, yet the screen is definitely not 100% dark). Anyway, I don't really care.

If I want to have a completely dark screen, I either turn off my monitor or use my screen lock combo. At most, I maybe want to dim my screen a bit. Maybe.

AFAIK KDE is not a display manager.
But if your desktop goes completely dark when tuning the light slider all the way down, you wouldn't be able to see anything, and how then would you turn it up again? If you don't have an alternative way to regulate than the slider KDE provides.
Seems like a decent precaution to me, if you really want it all black there are other ways, like turning off your monitor, or just use powersaving, or use a black screensaver. Alternatively you can make an app in a few seconds in for instance Lazarus, that goes full screen black. And would be easy to close again when you want the picture back.

The brightness on a TV or monitor doesn't go to all black either. IDK if it's a coincidence, but my monitor adjustment, and adjustment in KDE look identical when I have one at 100% and the other all the way down.

KDE is not a display manager

KDE is sometimes still synonymous with KDE Plasma, although the standard display manager for Plasma is now SDDM. So maybe they are talking about SDDM. Although I have a suspicion that this is nothing to do with SDDM and is instead a Plasma behavior.

Does the Display Manager control the brightness? I thought the Desktop Environment would. But what you're saying, is that SDDM doesn't go fully black when brightness is set to 0%, but other display managers do? TIL!

Þe DE may provide controls, but it doesn't do þe brightness itself. Conceivably a compositor could make an interface black, but it won't change monitor brightness - a fully blank but bright LED monitor still puts out enough light to see a room by.

Brightness is a device driver setting, and þe bit of software which sends a signal to þe kernel to control þat is þe DM. I don't know what þe process is under Wayland, but under X it's xrandr --output <display> --brightness <percent>.

thanks for the explanation. I always get confused between what does what between the display manager, login manager, and compositor.

Is my understanding correct though that SDDM has nothing to do with the behvior OP is observing?

Right; it's X. And it's a good point: I said "Display Manager" and þat's incorrect. It's X11 doing it, and X is a Display Server. Under Wayland, it'd be Wayland I'd guess, also serving as a display server. Good catch!