Latest LibreElec Generic running on GMKtek G3 Plus w Intel n150 failing to display at 2160p on JVC Projector (1080p fine)

    Basically the title, but I just installed LibreElec Generic on the GMKtek G3 Plus. Everything is working fine, including displaying via HDMI to my PC monitor, and displaying through my JVC projector (connected to Marantz preamp) in the theater at 1080p. But as soon as I switch to 2160p the screen simply blanks out. I wait a few seconds, and it returns back to the earlier 1080p setting (as expected, since I was unable to confirm that 2160p was working). Does anyone have any ideas or suggestions? Bit of a bummer, as I was hoping to use this as the replacement for the Nvidia Shield Pro in the theater. Thank you!

    The problem description suggests you're trying to set the Kodi desktop resolution to 4K (and users typically pick 4K60) which you probably don't want to do. Have a read here first: https://wiki.libreelec.tv/configuration/4k-hdr

    If the device won't switch to any 4K modes (or perhaps modes above 4K30) for playback, the normal cause is HDMI cables that won't support the bandwidth required, or a mismatch between the colour output on the HTPC and input on the TV, e.g. TV only allows 4:2:0 input and you're sending 4:2:2 or some RGB format.

    The additional dice-roll on inexpensive Intel devices is that the HDMI outputs are often derived from DP using an LSPCON chip which has its own firmware (can be buggy or needing updates) which influences the capabilities of the HDMI chain as this is cheaper to manufacture than wiring up a dedicated HDMI display transciever on the board. Some users find they need to use the DP outputs with an external DP to HDMI adapter to avoid problems with the internal one. Of course, the external DP to HDMI convertor also has a chip (with firmware) so they are not all equal, but unlike the internal convertor you can order a few different ones from Amazon and then return them if they didn't work.

    For some users it all just works fine. Others have a more frustrating experience. We'd love to meet the Intel engineer who first came up with the idea of using LSPCON chips with their NUC designs (which everone has copied since). Preferrably in a dark alleyway so we can thank them properly for all the extra support work and frustration we've encountered since then.

    I don't believe that LSPCON is still used in Alder Lake+ designs.

    The display block in older Intel GPUs (Gemini Lake, Tiger Lake) could provide only one HDMI 2.0 port natively. Some of those NUC designs had two HDMI 2.0 ports, so they had to use a DP-to-HDMI converter. Some devices had one native port + one port via DP LSPCON.