[x86-64] Asus NUC 15 Pro not displaying on LG OLED TV

    Hello all, I recently installed LibreElec 12.2.1 on my Asus NUC Pro (this guy). The install was easy, and the first half-day was spent with the NUC plugged into my monitor (also an LG, interestingly enough) via the HDMI port, which worked flawlessly. I got NFS shares set up for movies and tv, the web interface enabled, all was working swimmingly, until I moved it to my media room setup.

    The media room setup has the NUC plugged into a Denon AVR-X3700H (via the first HDCP 2.3 HDMI port, labeled 'CBL/SAT'), and from there goes to my LG OLED via the HDMI Out HDCP 2.3 port with eARC (happy to share a diagram or photo if there's interest). I have other devices flowing through the Denon that display without issue - Nintendo Switch, a PS5, etc. I did update the Denon firmware at the beginning of the month, so I'm reasonably confident it is at some flavor of "the latest".

    The LibreElec machine boots up and gets on the network just fine. I can hit the webUI and ssh ports without incident, but I cannot seem to get the device to display on my television.

    The 'pastekodi' command seems to be having trouble getting its data off the machine, but 'pastekodi -c' gives me, among other things, just pages and pages of lines of:
    2025-11-11 16:45:05.120 T:962 info <general>: CAESinkALSA - Unable to open device "hdmi:CARD=PCH,DEV=0,AES0=0x04,AES1=0x82,AES2=0x00,AES3=0x00" for playback
    2025-11-11 16:45:05.120 T:962 info <general>: CAESinkALSA - Unable to open device "hdmi:CARD=PCH,DEV=0" for playback
    2025-11-11 16:45:05.120 T:962 error <general>: CAESinkALSA::Initialize - failed to initialize device "hdmi:CARD=PCH,DEV=0"
    2025-11-11 16:45:05.120 T:962 info <general>: CAESinkALSA::Initialize - Attempting to open device "hdmi:CARD=PCH,DEV=0"
    2025-11-11 16:45:05.120 T:962 info <general>: CAESinkALSA - Unable to open device "hdmi:CARD=PCH,DEV=0,AES0=0x04,AES1=0x82,AES2=0x00,AES3=0x00" for playback
    2025-11-11 16:45:05.120 T:962 info <general>: CAESinkALSA - Unable to open device "hdmi:CARD=PCH,DEV=0" for playback
    2025-11-11 16:45:05.120 T:962 error <general>: CAESinkALSA::Initialize - failed to initialize device "hdmi:CARD=PCH,DEV=0"
    2025-11-11 16:45:05.120 T:962 error <general>: CActiveAESink::OpenSink - no sink was returned
    2025-11-11 16:45:05.120 T:961 error <general>: ActiveAE::InitSink - returned error
    2025-11-11 16:45:05.621 T:962 info <general>: CActiveAESink::OpenSink - initialize sink
    2025-11-11 16:45:05.621 T:962 info <general>: CAESinkALSA::Initialize - Attempting to open device "hdmi:CARD=PCH,DEV=0"

    The rest I believe I've captured here -

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    If there's any other output I can provide, please let me know and I would be happy to get it in a timely manner. Many thanks in advance!

    The "pastekodi" command is probably failing due to the size of the log (limits on the paste server are generous, but there are limits) and the Kodi log is zero value because it's captured hours after boot, so it has rotated and useful info shown during initial startup is no longer present. It also looks like you copy/pasted from a terminal session as some text is truncated (not a major thing..).

    The OS seems to have an issue with the iwlwifi card as this is throwing errors. Not sure it's too important but it adds to the log noise and might indirectly impact on other aspects of boot. Nothing else really stands out to me.

    However, audio capabilities in Kodi are determined from EDID data on the HDMI connection at startup. If Kodi cannot see/find audio hardware either the kernel doesn't detect it, correctly or (more likely in this case) something is messing with EDID data.

    I'll make an educated guess that the HDMI output spec from the NUC is not aligned to the HDMI spec of the input on the AVR, e.g. something like the NUC only supporting 4:2:0 and the AVR requiring 4:2:2. It reads a little like you picked "the best port" for input on the AVR but instead of ensuring best results this could be counter-productive and you might need to swap to another (lesser) input port or experiement with changes to the HDMI spec support of the port to make things work. I'm being a little vague about things here because different vendors name things differently. The important thing to understand is that HDMI is a collection of standards (interpreted by vendors) not 'a' standard.

    I would also experiment with cables (only use HDMI 2.0 certified ones) and the second HDMI port on the NUC, and also external DP to HDMI adapters instead of the HDMI output sockets on the NUC. The reason being that most NUC like boxes omit proper HDMI transciever hardware to save $$ and instead uses an internal DP to HDMI adapter (aka LSPCON chip) which contains closed-source firmware doing magic and imposing unseen limitations on the display chain - they are often oriented towards output on monitors more than TV's. Make sure the BIOS/firmware of the NUC and if separate any LSPCON firmware updates are applied as they can/do contain bugs. The advantage of external DP > HDMI adapters is that they aren't soldered to the motherboard inside the box so you can order a bunch of different ones and experiment until you find one that works. NB: There is also a long-running 'Denon AVR' thread elsewhere in the forums that you can read, but IIRC the main conclusion of that thread is people ditching the internal HDMI ports for external DP > HDMI adapters. The tertiary challenge is that different brands of adapters are available in different parts of the world, and even if the same brand is available there's no guarantee the LSPCON chip and firmware inside the latest batch of adapters is the same as the chip and firmware that someone tested a year ago and worked great. LSPCON chips in NUC boxes has been "the gift that keeps on giving" for HDMI support issues since they first appeared 6-8 years ago.

    Note to self .. I should scrape this text ^ into a wiki article, it's not the first time I had to write it all out long-hand :)

    thank you very much for this detailed and helpful reply! I am currently using Monster HDMI cables, "black platinum", for all the HDMI connections. I am intimately aware of the useless marketing Monster promulgates, but I had issues getting 4k off my Playstation until I started using Monster cables. I hate having to support such behavior, but... dammit I also want my 60fps :D

    I'm in the US, if that helps narrow things down. Are there brands of HDMI cables or DP adapters the community consistently has good experience with, or should I just buy Monoprice and hope for the best?

    I will check/update my NUC firmware TONIGHT, and report back if there is any positive change. Thanks so much again for the detailed and helpful reply!

    Alright, I updated the firmware, and progress! I can now somewhat-reliably get video, but when watching media it "blinks" intermittently every few (10-60) seconds. Screen goes completely black for approximately 1/3rd of a second (sound is uninterrupted) and comes back. I took the liberty of generating a pastebin (this time pastekodi worked great) in case something blindingly obvious is in there:

    https://paste.libreelec.tv/engaged-beetle.log


    For folks in the future following along, this is the ASUS NUC 15 PRO+ RNUC15CRSU50000U, updating to firmware CRARL579.0027 EBU (ver 0027) with SHA-256: 479A9589F2B1E9C1081C2C6AF0E0BA44A440FB99548F1B37300CAFA5CA1C06CB.

    booting LibreElec 12.2.1 with the second HDMI port presents no picture, but I can hear the menu-options change with the default 'click click' sound. pastekodi - https://paste.libreelec.tv/nice-pony.log

    Swapping the cable back to the first HDMI port also presents no picture.

    Updating to 'nightly-20251112-049eb6e' (HDMI cable in first port) gives no picture from boot. Additional attemps to display picture (going to the LG "Netflix" app and browsing back to "HDMI 2" where the Denon is connected) also gives no picture, but I can also hear menu-options change with the default 'click click' sound.

    pastekodi for nightly - https://paste.libreelec.tv/normal-shepherd.log


    How might a curious mind put Kodi into debug-mode via ssh?

    Code
    video=HDMI-A-1:1920x1080M@60D

    Make /flash writeable with mount -o remount,rw /flash then edit /flash/syslinux.cfg in nano and append ^ to kernel boot params (put everything on a single line). Reboot with the HDMI cable connected to HDMI-A-1 and see if forcing the initial DRM connector state to 1080@60 solves the problem?

    If not, create /storage/.kodi/userdata/advancedsettings.xml with the content below and reboot:

    XML
    <?xml version="1.0" encoding="utf-8" ?>
<advancedsettings version="1.0">
  <general>
    <settinglevel>3</settinglevel>
  </general>
</advancedsettings>