RPI 4B no video signal after LG Tv started from previous standby

    This is the same as reported by MatteN in the thread "RPi 4B - USB issues with latest kernel" however that thread was concerning a problem with a Mygica DVB USB stick, but then got added to by this particular problem.

    Kodi is left running all the time and the LG is put into standby with the remote. After a while, the TV is restarted and the message no video signal appears. At this point I observe:-

    Running top shows the status of kodi.bin is "Z" (zombie).

    Systemctl stop kodi fails to stop main thread.

    Systemctl reboot takes a very long time, but does fix the problem.

    Switching to live tv and back to RPI does nothing.

    The time the TV is in standby has an effect, if it is off for a short time the problem does not arise. In the attached log it took about 15 minutes for kodi to go into zombie state. This is probably because the TV may do Oled pixel cleaning when put into standby so does not go into deep sleep immediately.

    The log was produced with debug turned on and libCEC chosen. The tv was put into standby about 01:00 and turned back on at 01:17.

    Quote from Deri

    Kodi is left running all the time and the LG is put into standby with the remote. After a while, the TV is restarted and the message no video signal appears.

    Looks like you are using the Nightly/kodi 20 build. I assume that stable/matrix build works okay?

    The error relates to i2c, and may be fixed by this.

    Quote from MatteN

    I have stayed on LibreELEC-RPi4.arm-11.0-nightly-20220925-b1d73ad and the Pi is running fine for over 160 hrs now.

    I suspect this is using the last kernel 5.15, later nightlies are using 6.0.

    Quote from popcornmix

    Looks like you are using the Nightly/kodi 20 build. I assume that stable/matrix build works okay?

    The error relates to i2c, and may be fixed by this.

    Yes, it seems to have started with the move to kernel 6.0. I will keep an eye out for kernel 6.1 in the nightlies and test again.

    Udated to LibreELEC-RPi4.arm-11.0-nightly-20221026-bfa93a6, shut down tv for 1 hour, guess what? "No signal".

    Back to LibreELEC-RPi4.arm-11.0-nightly-20220925-b1d73ad again.

    Hi,

    I don't know if my case was same as your... RPi3B, LE 10 or 11, LG TV, and sometimes when I started the TV... no signal...

    In my case, if the RPi restarted when the TV was in stand-by, wasn't detect the TV at HDMI cable.

    The solution was using the "getedid create" command in the SSH terminal when the TV is on (and working with LE :) ). This is save the TV display parameters and on the startup the RPi will use it, and does not try to read it thru HMDI cable.

    And looks like working with RPi4B too:

    Post

    RE: LE10 fixed EDID on RPi4 - Scripts

    The "getedid" script works exactly like the one on x86, which is documented on the wiki https://wiki.libreelec.tv/configuration/edid

    "getedid create" makes current EDIDs permanent (this also honors a receiver on HDMI-2) and "getedid delete" deletes those.

    It would be great to get some more feedback if it all works (so far I think I'm the only one who tested this) or if there are issues I might have missed.

    so long,

    Hias
    HiassofT
    April 25, 2021 at 5:32 PM
    Quote from HiassofT

    Deri can you please test with the latest nightly build (2022-10-30)? It includes an RPi kernel update with the change mentioned by popcornmix

    so long,

    Hias

    Just did a test, it is different, no kernel oops, and all kodi threads continued running, but still no video signal when tv is turned back on. The log is here.

    The TV was brought out of standby at 17:17 and you can see several CEC messages when it comes to life and then pressed Ok on the remote.

    There is a warning "FIXME" message at 16:25:14.235, which is roughly the time I pushed the power button on the tv remote to put it into standby.

    I shall repeat the test tonight with the 25/09 nightly, to see if the same warning occurs (to see if this is a red-herring or not).

    Quote from Deri

    I shall repeat the test tonight with the 25/09 nightly, to see if the same warning occurs (to see if this is a red-herring or not).

    No, it was a red herring. The 25/09 version has the same warnings.

    I have noticed that the latest nightly does have the same kernel oops as in the original log. So favourite is the popcornmix fix scheduled for linux 6.1, maybe it has not been back ported to 6.0.5 properly.

    Quote from Deri

    I have noticed that the latest nightly does have the same kernel oops as in the original log. So favourite is the popcornmix fix scheduled for linux 6.1, maybe it has not been back ported to 6.0.5 properly.

    You are correct. I've just checked and the fix from 6.1 is missing from 6.0 tree. I've cherry-picked it to rpi-6.0.y, so should appear next time LibreELEC bumps their kernel version (probably best to wait for confirmation here, as that's not an automatic process).

    Quote from popcornmix

    You are correct. I've just checked and the fix from 6.1 is missing from 6.0 tree. I've cherry-picked it to rpi-6.0.y, so should appear next time LibreELEC bumps their kernel version (probably best to wait for confirmation here, as that's not an automatic process).

    Thank you for your continued tireless and often thankless work for the RPi community. I will test this fix when it is available in the upstream. I have been a member of the community for years now and want to thank you for being such a force of good in this community.

    This problem is occurring for me because I think the latest update (10.0.3) broke the Turn Off screensavers vcgencmd compatibility and using dpms results in a display that won't come back properly. I managed to get the display back briefly but it only showed a still frame. Had to restart to restore full video. Hopefully this will fix that problem when it's available in the nightly. Thanks again, much appreciated!