LG OLED C8: missing screen refresh rate?

1st Official Post

    Hello,

    I upgraded my TV from panasonic Plasma (fullHD) to new LG OLED C*. I restarted kodi and see the correct resolution (3840x2160p) but i only have refresh rates of 30 and below. I need to configure 50Hz as that's what livetv is using. Can someone explain how to add this missing refresh rate? I tried to delete guisettings.xml but after reboot 50Hz is still missing.

    Regards,

    Frans

    Depends on the hardware you are using - do you know if it can output 4k above 30Hz? Some platforms can. Plenty cannot. But since the live TV source I am guessing is not 4k, you could set 1920x1080 and let the TV upscale which would probably be better. The LG upscaler from full HD to 4K is pretty decent. And if your box can output 4k, it will still be able to switch to that resolution when you play 4k media.

    Quote from posixx

    Running ASRock Fatal1ty Z270 Gaming-ITX/ac LGA1151 HDMI 2.0 ITX Motherboard with Intel 7th Gen Core i7 7700T so that shouldn't be any problem looking at the specs:

    Supports HDMI with max. resolution up to 4K x 2K (4096x2160) @ 60Hz

    Nice board! Just a thought - do you know whether the HDMI firmware fror the LSPCon chip is up to date? (current is v1.66). That's the chip that converts the display port signals to HDMI, since the HDMI from the CPU/GPU can't do it natively. I don't know if that would cause the problem you're seeing, but it will affect some of the 4k capabilies when it comes to getting HD audio over HDMI to work.

    How to check that? I searched the BIOS but couldn't find any FW number. Also i installed Libreelec from scratch and the same result:

    Screen 0: minimum 8 x 8, current 1920 x 1080, maximum 32767 x 32767

    DP1 disconnected primary (normal left inverted right x axis y axis)

    DP2 disconnected (normal left inverted right x axis y axis)

    DP3 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 0mm x 0mm

    1920x1080 60.00 + 120.00 100.00 119.88 50.00* 59.94 30.00 25.00 24.00 29.97 23.98

    4096x2160 24.00 23.98

    3840x2160 30.00 25.00 24.00 29.97 23.98

    1920x1080i 60.00 50.00 59.94

    1280x720 60.00 50.00 59.94

    1024x768 60.00

    800x600 60.32

    720x576 50.00

    720x480 60.00 59.94

    640x480 60.00 59.94

    HDMI1 disconnected (normal left inverted right x axis y axis)

    HDMI2 disconnected (normal left inverted right x axis y axis)

    VIRTUAL1 disconnected (normal left inverted right x axis y axis)

    So i'm missing the refresh rates above 30Hz on 4K.

    Frans

    Quote from posixx

    How to check that? I searched the BIOS but couldn't find any FW number. Also i installed Libreelec from scratch and the same result:

    Not having a board with that feature I am not 100% certain. I recall reading previously that it was often only updatable via Windows, which is a pretty poor solution for anyone using the board for anything else. I imagine that the update utility would tell you what the version is, but I am somewhat surprised that the ystem does not report it somewhere. Maybe someone else with a board using the LSPCon chip can comment...

    Ok, i made a WinToUSB flash disk and booted windows 10 pro. After installing some drivers like videocard i was able to read and update the LSPCon firmware; the current firmware version was 1.61, i upgraded to 1.66.

    Within windows i was able to set 3840x2160 with 50Hz refresh rate without any problems; it even has 60Hz available.

    Rebooting and removing the flash drive booted again into libreelec still highest refresh rate available at 3840x2160 = 30Hz. So it looks like a libreelec related issue. I hope someone can help solving this!

    One step further; i downloaded ubuntu dekstop and booted from that on USB. same output from xrandr. I removed my meridian UHD722 HDMI switcher from the chain and now i get 3840x2160 at 60Hz! So it looks like handshaking between meridian and LG is not accurate. I run Supra HDMI cabling which should have enough bandwith etc but to be sure i have ordere RU Connected HDMI cabling 10m optical and 2x 1m all support 4K @60Hz HDR / 4:4:4.

    Keep you posted

    After conversation with Meridian support i ordered AudioQuest HDMI cables as these are guaranteed by meridian to deliver the required bandwith (18,2 Gbps). But, when testing i get exactly the same results. This looks like a Meridian UHD722 problem to me. It simply does not report all supported resolutions and refresh rates to the source.

    Hello,

    I was very busy the pas month so no time to test it out. Today a firmware upgrade of my Meridian swithing device was available. After that the same issue. But using the latest community build (LibreELEC-Generic.x86_64-8.2.5-3.42.2-4.14.44.img.gz) now 3840x2160 at 50Hz and 60Hz are available!

    Great work sky42! Hopefully this will make it soon into the release builds.