Raspberry 4, Libreelec 10.0.1, no picture after reboot

  • busfahrer303 first add "drm.debug=0x04" to the end of /flash/cmdline.txt (after "quiet", all on the same line) to get some more debug info, then reboot and reproduce the issue.

    After that ssh in, run "pastekodi" and post the URL you got.

    so long,

    Hias

  • busfahrer303 Seems like the 60Hz mode isn't part of the whitelist:

    Do you use an HDMI 2.0 or 2.1 cable? If you are using a lower HDMI version cable, it's possible that the whitelist is incomplete.

    PS: Whitelist AFTER re-enabled TV is wrong:

    Code
    Feb 02 16:29:47.632820 LibreELEC kernel: [drm:drm_helper_probe_single_connector_modes] [CONNECTOR:32:HDMI-A-1]
    Feb 02 16:29:47.632865 LibreELEC kernel: [drm:drm_add_display_info] Supported Monitor Refresh rate range is 0 Hz - 0 Hz
  • Da Flex The HDMI-cable is 2.1. I don't think that it has to do with cable. Because after rebooting the RPI4 it works. And also when I switch from 30Hz to 60Hz in the setting it works. Can I setup the whitelist manual?

  • Thanks for checking the cable. The default whitelist seems to be complete, but the TV is sending wrong refresh capabilities after being re-enabled.

    I suggest to go into the "CEC Adapter" menu at LE's input settings. There is a setting, which keeps HDMI signal always on, even if the TV gets switched off. If you activate this setting, then hopefully no HDMI negotiation happens when TV comes back.

  • Thanks for your answer and support. Normally I had switched off the CEC-adapter in the settings. But for testing now I switched it on. I don't find the setting where I can keep HDMI signal always on. Can you explain it little bit more. Thank you so much.

  • I tested both:

    1. "When the TV is switched off" should be set to "Ignore"

    2. cmdline.txt: boot=UUID=1108-5701 disk=UUID=3542a3ff-9e05-4d2b-80ce-0438958f4de6 quiet video=HDMI-A-1:3840x2160M@60

    3. combination of 1. and 2.

    Result ist the same. I switched of my screen, wait 10s, switched it on and then I have no picture from RPi4. When I switch the refresh rate to 30Hz, everything works fine.

    Some more ideas? Thanks.

  • busfahrer303 please provide some more infos about your setup:

    Are you connecting the RPi directly to a TV or via an AVR?

    Which TV and/or AVR models are you using?

    If you have an AVR in the chain, does it work if you connect the RPi directly to the TV?

    It sounds like scrambling re-negotiation, which is needed for 4kp50/60, isn't quite working but I haven't spotted any obvious errors in the logs yet.

    so long,

    Hias

  • HiassofT That was a good idea :)

    The TV was connected via AVR. TV-model: Samsung GQ49Q70RGTXZG, AVR-model: Onkyo TX-NR696. I connect the RPi now directly to the screen and it works fine. I looks like a problem by connect via AVR. I have the same problem when I switched the output on AVR to beamer. Hope this will be helpfull for you to find a solution.

    Thanks so much

    Thomas

  • busfahrer303 are you running the latest firmware on your Onkyo AVR? Looks like latest one is from January this year

    Firmware Updates TX-NR696 | ONKYO Asia and Oceania Website
    Follow the link to the latest Onkyo firmware update for the TX-NR696
    www.intl.onkyo.com

    Might also be worth checking the various settings of the AVR and/or searching the net for similar problems - issues with buggy AVR firmwares are not too uncommon...

    so long,

    Hias

  • HiassofT Yes, I have the newest firmware installed on AVR. I'm not convinced it's an AVR problem. I also use Apple TV. There I set the same resolution and screen refresh rate as on the RPi4. This works fine with the Apple TV.

    Or do I have a problem of understanding?

    Thanks

    Thomas

  • Da Flex again:

    I'm not convinced it's an AVR problem. I also use Apple TV. There I set the same resolution and screen refresh rate as on the RPi4. This works fine with the Apple TV.

    Or do I have a problem of understanding?

    Thanks

    Thomas

  • I think it's an AVR problem. The 0Hz refresh rate (see post #39) comes from the AVR, and that's wrong. Apple TV seems to handle re-connections differently, but details are hard to get without HDMI monitor.

  • busfahrer303 can you check if the AppleTV outputs 4:2:0 YCbCr ("YUV"), 4:2:2 YCbCr or 4:4:4 RGB/YCbCr?

    If it outputs 4:2:0 YCbCr (which is quite a common default config) then you won't run into scrambling issues with it as that format doesn't need high bandwidth / scrambling for 4kp60 output.

    The RPi4 however doesn't support 4:2:0 YCbCr so it'll need higher bandwidth (which requires scrambling) for 4kp50/60.

    I won't rule out that there could be a bug somewhere in the video driver code, but it could also be that it's a bug in the AVR but you didn't hit it with the Apple TV.

    so long,

    Hias