Hey folks,
I’m having an issue with KDE Plasma, where in the Brightness & Color applet, only color is being shown. After reboot, brightness is also shown and adjustable, but after some time (and probably after screen locking, not 100% sure) the brightness control disappears and only color/night light is adjustable.
Has anyone experienced anything similar? Any ideas?
Thanks!
I’ve recently switched from a cheapo 24" FullHD Monitor to an new one which has its controls properly implemented (for the most part) via i2c. And only since then KDE Plasma gives me the option to control the brightness via an adjustment slider.
In short with ddcutil detect you can check your current display. It will include it’s current address on the i2c bus - e.g. /dev/i2c-DIGIT. With that address, with DIGIT being one number between 0-11 (or higher, depending on your hardware), you could run ddcutil capabilities --bus=DIGIT and when brightness isn’t listed … I guess KDE Plasma can’t really tell how to address the brightness control properly ?!
Long story short, I adjust my screen brightness quite often. And via shortcuts I was able to adjust the brightness on the old monitor despite the fact that the slider wasn’t available within the display tray icon widget. You’ll find these within the power management options, not within the section display configuration.
That might be not based on the same issues you’re facing, But I guess that workaround is at least worth a shot.
Thanks for your input.
Here is the ouput of ddcutil capabilties (I have a brand new Dell Ultrasharp 27" 4K Monitor)
Model: U2723QE
MCCS version: 2.1
Commands:
Op Code: 01 (VCP Request)
Op Code: 02 (VCP Response)
Op Code: 03 (VCP Set)
Op Code: 07 (Timing Request)
Op Code: 0C (Save Settings)
Op Code: E3 (Capabilities Reply)
Op Code: F3 (Capabilities Request)
VCP Features:
Feature: 02 (New control value)
Feature: 04 (Restore factory defaults)
Feature: 05 (Restore factory brightness/contrast defaults)
Feature: 08 (Restore color defaults)
Feature: 10 (Brightness)
Feature: 12 (Contrast)
Feature: 14 (Select color preset)
Values:
01: sRGB
04: 5000 K
05: 6500 K
06: 7500 K
08: 9300 K
09: 10000 K
0b: User 1
0c: User 2
Feature: 16 (Video gain: Red)
Feature: 18 (Video gain: Green)
Feature: 1A (Video gain: Blue)
Feature: 52 (Active control)
Feature: 60 (Input Source)
Values:
1b: Unrecognized value
0f: DisplayPort-1
11: HDMI-1
Feature: AA (Screen Orientation)
Values:
01: 0 degrees
02: 90 degrees
04: 270 degrees
Feature: AC (Horizontal frequency)
Feature: AE (Vertical frequency)
Feature: B2 (Flat panel sub-pixel layout)
Feature: B6 (Display technology type)
Feature: C6 (Application enable key)
Feature: C8 (Display controller type)
Feature: C9 (Display firmware level)
Feature: CC (OSD Language)
Values:
02: English
03: French
04: German
06: Japanese
09: Russian
0a: Spanish
0d: Chinese (simplified / Kantai)
0e: Portuguese (Brazil)
Feature: D6 (Power mode)
Values:
01: DPM: On, DPMS: Off
04: DPM: Off, DPMS: Off
05: Write only value to turn off display
Feature: DC (Display Mode)
Values:
00: Standard/Default mode
03: Movie
05: Games
Feature: DF (VCP Version)
Feature: E0 (Manufacturer specific feature)
Feature: E1 (Manufacturer specific feature)
Feature: E2 (Manufacturer specific feature)
Values: 00 02 04 0C 0D 0F 10 11 13 0B 1B 1A 14 23 24 27 3A (interpretation unavailable)
Feature: E5 (Manufacturer specific feature)
Feature: E7 (Manufacturer specific feature)
Values: 02 03 (interpretation unavailable)
Feature: E8 (Manufacturer specific feature)
Feature: E9 (Manufacturer specific feature)
Values: 00 01 02 21 22 24 (interpretation unavailable)
Feature: EA (Manufacturer specific feature)
Feature: EF (Manufacturer specific feature)
Feature: F0 (Manufacturer specific feature)
Values: 00 05 06 09 0A 31 32 34 36 (interpretation unavailable)
Feature: F1 (Manufacturer specific feature)
Feature: F2 (Manufacturer specific feature)
Feature: FE (Manufacturer specific feature)
Feature: FD (Manufacturer specific feature)
Brightness is listed, but not available in KDE until after I reboot and then only for some time period…
I could not find any options within power management to apply shortcuts to the brightness settings…
So, I reapplied the power profile in power management settings (it was set to “Leave unchanged”) and now when I actively set it to “Balanced” (or the other two) I have brightness control again.
Weird.
Thanks anyway!
I guess that’s just a bit confusing due to the fact that the main use case for monitor brightness controls are primarily being used on Laptops and is therefore included in the power profiles.
Still somehow buggy, thought it was the power profiles but it wasn’t.
I don’t have brightness control after screen unlocking, so I have now set an alias in my terminal to
systemctl --user restart plasma-powerdevil.service
as a quick fix. After powerdevil restart it works again.
Maybe some timeout issue after standby or something?