rpi4b and LG OLED C1 - cannot output 4K correctly

I am experiencing a strange "bug" with Kodi 4K rendering on RPi4b. It did not work in LE v11, and still does not work in LE v12.

I have LG OLED C1 and Kodi user interface set to be rendered in 1920x1080@100Hz. I have however whitelisted all 4K modes (as per wiki https://wiki.libreelec.tv/configuration/4k-hdr#id-4k-60hz) and all Full HD modes.

Now, when playing 4K content (SDR, HEVC) the TV switches into 4K mode, but the movie is rendered in what seems to be a Full HD res (1920x1080) into the first quadrant. If I un-whitelist the 4K modes, the TV does not switch into 4K mode and the movie is again rendered in Full HD res correctly (and upsampled to 4K by TV). So it looks, like for some reason Kodi downsamples the content regardless the mode the TV is in.

This is how it looks:

I could have missed something fundamental in Kodi settings, but after several reviews I am still clueless. Anyone has any insight?

Quote from Da Flex

So enable "Adjust Refresh".

"Adjust Refresh" is, following the advice in the same wiki, set to "On Start/Stop".

Quote from chewitt

Please share a debug log that demonstrates the problem. Thanks.

I am currently only able to access the box remotely, so will have to see, if I could enable and replicate this somehow.

Quote from MatteN

Under the years i have used Pi4 with LE and LG Oled something similar happened only once and it went away when i replaced the HDMIcable.

There is one tricky thing I did not fully realize - I am using Argon case with SSD port. I had to originally replace the board with HDMI convertors because one did not work. Then I read here that Argon cases are not very reliable with respect to HDMI. So I wonder if this might be a culprit.

So far my reasoning about this not being the cable (or the HDMI output itself) is that apparently the TV switches into right res (4K), but for some reason Kodi turns on the downsampling anyway. I would expect if the hw negotiation of 4K mode fails, it would not switch into it in the first place.

Quote from chewitt

Please share a debug log that demonstrates the problem. Thanks.

Not sure what to log I chose "video" and "video and audio timing" in "components" list. I just tried to start playing the file (which was 4K HEVC mov created by me) and when the playback started and it was obvious it was wrong I stopped it. Then I stopped the logging.

I did few more tests since the issue is still there (with LE 12.0.1). Apparently it does not depend on the video content/format. Just switching the Kodi UI to 2160p has exactly the same effect - the TV switches into 4K, and Kodi outputs its UI into the top left quadrant at 1080p.

I just got a new Google TV Streamer so I could verify that the HDMI port/setting on the TV and the cable are not a problem, with the Streamer switching to 4K@60Hz with both SDR and HDR content without a hitch.

I recorded a log from "video", "audio" and "D-bus" components, not sure it helps though:

It captures changing the UI resolution from 1080p@100Hz to 2160p@30Hz and back again when the "accept the new resolution" dialog times out. When in 4K mode, the Kodi System Info reports correctly that the resolution is indeed 2160p@30Hz - full screen. Just the UI is rendered in 1080p into the top left quadrant.

Just to note: the EGL_BAD_SURFACE error seems to be present at every resolution change (even those that work correctly).

So if anyone has an idea, what might be wrong, I am all ears.

Quote from chewitt

The number of users that show up with an Argon case and swear it cannot possibly be their magic/favourite case; who then go quiet after we insist they remove the board and test playback without it .. is notable. So, remove the board and test.

That seems to be next logical step. Unfortunately I do not have a micro HDMI cable at hand at the moment and I get to testing this only few times a year when visiting my dad. And I won``'t get a new cable before I leave. So I if I go silent, it was not because I got faulty Argon case.