When I first connected my TV, I was shown options to mirror, extend, or otherwise configure the external display. That menu no longer appears, even after disconnecting and reconnecting the cable, and I cannot find the options in the display settings. I also noticed that the external screen is limited to 4K at 30 Hz. Could that be because the displays are extended rather than mirrored? I'm using an optical HDMI cable that supports 4K at 120 Hz, and the same setup works correctly in Windows. What settings or shortcut should I check?
2 Answers
The 4K/30 limitation may be separate from the mirroring setting. Check the HDMI port on the computer and TV, the GPU driver, and whether the cable is connected through an adapter or dock. Mirroring can also force both displays to use a resolution and refresh rate supported by the slower display, but it normally wouldn’t be the only reason a capable setup is limited to 30 Hz. In the display configuration panel, select the external screen directly and see whether 3840×2160 at 60 or 120 Hz is available.
What desktop environment are you using? CachyOS is the distribution, while the display controls depend on whether you’re running KDE Plasma, GNOME, or something else. If you’re using KDE Plasma, try pressing **Meta (the Windows key) + P** to open the display mode chooser. You can also check **System Settings → Display & Monitor → Display Configuration** for the mirror and extend options. A screenshot of that page would help if the controls are missing.
I thought DE meant the distribution, so I only mentioned CachyOS. I’ll try the Meta + P shortcut and check which desktop environment I’m running.