LG C4 recently no higher than 4k/60?

General system Gaming, sound and video
1

hey all, anyone out there using an LG OLED at 4k/120 hz?

i was, but as of yesterday’s system update i’ve lost the option to set to 4k/120. AND, the problem is also there on LTS.

i used to be able to do 4k@120 with FreeSync and HDR, at 4:2:0 subsampling, but now that option no longer exists.

i’m on KDE+Wayland.

xrandr isn’t reporting any other refresh than 60.

i’ve tried LTS kernel, turning off: 4:4:4 passthrough, VRR, HDR, but no change.

GPU: Radeon 7900 XTX

driver: mesa

HDMI 2.1

no other monitors.

any thoughts are appreciated. thanks!

2

I have a LG OLED C1, also a 7900XTX and I am also using KDE Plasma on Wayland.

I have no issues currently, everything is working fine. I am not using HDR tho.

I am using a DisplayPort to HDMI adapter to get full 4k120 RGB / 4:4:4 without subsampling. It is a DisplayPort 1.4 adapter so display stream compression is active of course. But it works fine and Freesync / VRR works too.

It is this adapter:

I am using this firmware:
https://kb.cablematters.com/index.php?View=entry&EntryID=160

There seems to be a newer firmware but it looks like it’s specific to macOS and I haven’t tried it since I have no issues with the older firmware:
https://kb.cablematters.com/index.php?View=entry&EntryID=147

You will need Windows to update the firmware tho.

3

neat, thanks! yeah, i dunno where the issue is. if it’s plasma, mesa, wayland. no clue why it changed and i can’t get it back.

i’ll take a look at this adapter. i have a VM for such firmware things.

4

would you mind enabling HDR in plasma display settings just to test for me? let me know if anything changes before i buy this device?

thanks!

5

Turned on the TV → enabled it in the Plasma display settings → turned on HDR in the Plasma display setting → the TV detect HDR content and automatically switched to a HDR mode and it reports the input signal as 4k120 RGB 10b HDR10.

Also checked the newer firmware package. I’d stick with https://kb.cablematters.com/index.php?View=entry&EntryID=160

The newer one looks like it’s meant for macOS / Mac Books and the normal version included has a lower version number than the one from 2023 (for some reason)

1 Like
6

perfect! thank you i’ll give it a go!

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