Dim screen option missing on Gnome 43

[salvocos]

Hello to everybody in this great community.

I am using an Minisforum HX90 (with AMD 5900hx) connected to smart TV (TCL C835) through HDMI.
I want the screen to dim (going almost black) when idle, in order to save power, but the dim option is missing under GNOME settings -> power.

Is there any body who knows why is this happening?
Maybe it is an hardware related problem?

Following is the output of inxi -SGxxx:

System:
  Host: hx90gnome Kernel: 6.1.13-1-lts arch: x86_64 bits: 64 compiler: gcc
    v: 12.2.1 Desktop: GNOME v: 43.3 tk: GTK v: 3.24.36 wm: gnome-shell dm:
    1: GDM v: 43.0 2: LightDM v: 1.32.0 note: stopped Distro: EndeavourOS
    base: Arch Linux
Graphics:
  Device-1: AMD Cezanne [Radeon Vega Series / Radeon Mobile Series]
    driver: amdgpu v: kernel arch: GCN-5 pcie: speed: 8 GT/s lanes: 16 ports:
    active: HDMI-A-2 empty: DP-1,DP-2,HDMI-A-1 bus-ID: 04:00.0
    chip-ID: 1002:1638 class-ID: 0300 temp: 19.0 C
  Display: server: X.Org v: 22.1.8 with: Xwayland v: 22.1.8
    compositor: gnome-shell driver: X: loaded: amdgpu
    unloaded: modesetting,radeon alternate: fbdev,vesa dri: radeonsi
    gpu: amdgpu display-ID: :0 screens: 1
  Screen-1: 0 s-res: 3840x2160 s-dpi: 96 s-size: 1016x572mm (40.00x22.52")
    s-diag: 1166mm (45.9")
  Monitor-1: HDMI-A-2 mapped: XWAYLAND0 model: Beyond TV serial: 65536
    res: 3840x2160 hz: 60 dpi: 81 size: 1210x680mm (47.64x26.77")
    diag: 1387mm (54.6") modes: max: 3840x2160 min: 640x480
  API: OpenGL v: 4.6 Mesa 22.3.6 renderer: AMD Radeon Graphics (renoir LLVM
    15.0.7 DRM 3.49 6.1.13-1-lts) direct-render: Yes

[fbodymechanic]

Did you unplug this yet? I told you in the other thread it will not offer it to you until you remove external displays.

Monitor-1: HDMI-A-2 mapped: XWAYLAND0 model: Beyond TV serial: 65536
    res: 3840x2160 hz: 60 dpi: 81 size: 1210x680mm (47.64x26.77")
    diag: 1387mm (54.6") modes: max: 3840x2160 min: 640x480

For me, the option is not there when plugged into external monitors, and is only available when using the built in laptop screen exclusively.

[fbodymechanic]

For example: No monitors plugged in:

When I plug my monitor in:

[salvocos]

My computer is not a laptop, so I cannot use it without plugging it to a display.

So, you are suggesting that the dim option is not available, for example on Desktop computers?

[fbodymechanic]

Correct. It will not be available on a desktop or any compute rthat has a monitor plugged into it. If you would like to dim an external monitor you will need to use the settings from within the monitor itself.

[salvocos]

I am curious though. When I set the Screen Blank option, which works correctly, it would dim the screen a few second before turning it off.
Is there any obtain such behavior without completely turning it off?

[fbodymechanic]

I have no idea. Maybe someone else can chime in on that one.

[salvocos]

Thanks a lot anyway @fbodymechanic

[fbodymechanic]

I do what I can.