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.

    Thank you both! I am away from home right now, so I can’t test further, but when I get back I will try setting the Kodi UI to 1080p and then try to launch a few 4K video files. I “know” (or am pretty highly certain) that this is not a problem with HDMI cable or the receiver or projector capabilities as 1) it’s a high-end home theater that has five HDMI inputs through the chain, 2) the JVC projector/Marantz receiver combo has displayed 4K/60Hz content a million times (most recently through an Android AM6B+ running CoreElec, and finally, I tried the new NUC on three different HDMI cables (and then returned the previous devices to those inputs, which worked again). So, my best guess is that it’s an issue with LibreElec or perhaps the LSPCON chip mentioned earlier. Is there any sort of log or test I can do which might help diagnose the issue further?

    Update:

    Verified that the NUC works at 1080p for both UI and video playback, and in fact will play 4K videos (though reduced to 1080p during playback). This is for both 60 and 59.94 Hz. I had hoped that playing a 4K video would at least trigger 4K video playback, but no luck (just got the same blank screen for a few seconds before falling back to 1080p). Also removed the NUC and replaced the AM6B+ Android device with Kodi and played the same video, same high-end HDMI cable and verified it works fine.

    At this point I’m quite sure it’s not the HDMI cable, and am not sure what else I can check. Projector is JVC DLA-NX7, running through a Marantz AV8802 preamp, and I’ve never had issues with color output/input. Is there a specific test or log I can collect that might help? Happy to chase down whatever else I can if it’s helpful, with thanks!

    Please provide a full debug log.

    How to post a log (wiki)

    1. Enable debugging in Settings>System Settings>Logging
    2. Restart Kodi
    3. Replicate the problem
    4. Generate a log URL (do not post/upload logs to the forum)

    use "Settings > LibreELEC > System > Paste system logs" or run "pastekodi" over SSH, then post the URL link

    Thank you for those clear instructions!

    I first turned on logging, then tried to change from 1080p to 2160p, both 60 and 59.94 Hz. That log is:
    https://paste.libreelec.tv/enormous-dory.log

    I realized afterward that I had forgotten to reboot the machine/restart Kodi. So I did that, and this time:

    1. Verified 1080p UI was showing
    2. Launched 4k movie, verified it played (though downsampled to 1080p)
    3. Attempted change to 2160p in settings (leaving 60 Hz already selected) - failed
    4. Changed Hz to 59.94 (succeeded)
    5. Attempted change to 2160p again, failed

    This second log is: https://paste.libreelec.tv/suitable-quail.log

    Hope this helps!

    Quote from Ozyman

    Hope this helps!

    Not much. Please repeat after creating a plain SMB mount to the device where you store media, then play something appropriate and 4K from that source using the Kodi 'Videos' view so we can see a playback event containing all the normal and useful ffmpeg/drm/Kodi media debug info that's being masked or suppressed by the Plex plugin you are using. In the log you've captured I can sort of figure out where playback probably occurred, but there's no useful info.

    Done. I had issues mapping an SMB share, but NFS worked fine, so I used that.

    To try and clean things up even more, I reset LibreElec to factory defaults (which also removed the Plex plugin - PM4K).

    Test:

    1. Set UI to 1920x1080P when connected to my PC monitor (so I could see UI)
    2. Moved NUC down to theater, and connected to Marantz/Projector HDMI chain.
    3. Powered on, verified I could view UI at 1080P.
    4. Turned on logging.
    5. Launched 4K movie via Videos view - played, but at 1080p (as verified by projector popup)
    6. Submitted log: https://paste.libreelec.tv/just-goblin.log

    I can find the playback in the log, so I think it worked. Note that I did *not* try to set the Kodi resolution setting again this time, just to keep things cleaner. I only tried playing the 4K video as suggested. Thanks again!

    Code
    2025-08-13 19:08:23.604 T:976      info <general>: ffmpeg[0x208aae90]:   Stream #0:0: Video: hevc (Main 10), yuv420p10le(tv, bt2020nc/bt2020/smpte2084), 3840x2160 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn (default)

    ^ media is detected as 4K23.976 (10-bit, with a colourspace normally associated with HDR)

    Code
    2025-08-13 19:08:23.740 T:979     debug <general>: CRenderManager::Configure - change configuration. 3840x2160. display: 3840x2160. framerate: 23.98.
2025-08-13 19:08:23.745 T:892     debug <general>: DeleteRenderer - deleting renderer
2025-08-13 19:08:23.745 T:892     debug <general>: LinuxRendererGLES: Cleaning up GLES resources
2025-08-13 19:08:23.745 T:892     debug <general>: SetHDR: setting connector colorspace to Default
2025-08-13 19:08:23.745 T:892     debug <general>: LinuxRendererGLES::Configure: fps: 23.976
2025-08-13 19:08:23.745 T:892     debug <general>: SetHDR: setting connector colorspace to BT2020_YCC
2025-08-13 19:08:23.745 T:892     debug <general>: LinuxRendererGLES::Configure: HDR passthrough: on

    ^ then it flags a renderer with [email protected] and appropriate colourspace, but have you enabled "adjust reresh" ? - If yes it will output using the whitelist (not configured) or best guess at the right mode. If not, it will scale the output to the desktop res (1080@60). So make sure adjust-refresh is enabled and configure the whitelist as per the wiki article.

    Once done, if you run kmsprint on the SSH console before playback it will show DRM connector properties as 1080@60, and during playback it should show them to be [email protected]?