[RPi4] HDMI CEC not working with new TV

I used to have a Samsung KS8000 connected to LE running on an RPi4. HDMI CEC worked great on it allowing me to use the TV's remote to navigate the Kodi interfaces. I just got a Samsung QN90B and tried to use the TV's remote as before with no luck.

Just for laughs, I bumped to LE 10.95.1 (LE11 Beta 2) and updated firmwares but CEC didn't work either. I noticed libCEC was 4.0.7:

libCEC version: 4.0.7,  compiled on 2023-02-12 21:15:31 by docker@ff72e675fac3 on Linux 5.15.60-2-pve (x86_64), features: P8_USB, DRM, P8_detect, Linux

To make sure the TV was not faulty, I booted the RPi with Bullseye + vanilla Kodi, CEC worked just fine. Here:

libCEC version: 6.0.2, compiled on Linux-5.10.63-v8+ ... , features: P8_USB, DRM, P8_detect, randr, RPi, Exynos, Linux, AOCEC

In an attempt to find more info I dug deep into the internet and remember seeing some text about newer TVs use a newer CEC protocol and the two major version differences in libCEC might be what explains that. Do you have another theory?

I compiled 10.95.1 with libCEC 6.0.2 and it works great. I will raise a PR.

libCEC version: 6.0.2,  compiled on 2023-02-26 05:57:18 by miki@Miki-AW. on Linux 4.4.0-19041-Microsoft (x86_64), features: P8_USB, DRM, P8_detect, Linux

However, that makes no sense because there is no meaningful difference between libCEC 4.0.7 and libCEC 6.0.2. Am I missing something here:

Comparing libcec-4.0.7...libcec-6.0.2 · Pulse-Eight/libcec

USB CEC Adapter communication Library http://libcec.pulse-eight.com/ - Comparing libcec-4.0.7...libcec-6.0.2 · Pulse-Eight/libcec

github.com

Though I guess the reverse explains it:

Comparing libcec-6.0.2...libcec-4.0.7 · Pulse-Eight/libcec

USB CEC Adapter communication Library http://libcec.pulse-eight.com/ - Comparing libcec-6.0.2...libcec-4.0.7 · Pulse-Eight/libcec

github.com