RPi4 62Hz Refresh problem

    Is there a way to stop a RPi4 using 1366 X 768 X 62Hz at boot. All three of my TVs say its an illegal mode! On the particular TV I have had to go back to a RPi3 that uses 60Hz refresh at boot and does not cause a problem.

    However on the RPi4 with 62Hz the boot up screen image is torn if I power on the TV within about 5 seconds of power on at the wall. If I dont power on the TV within about 5 seconds the TV just displays a blank screen except for a torn version of the LibreElec version number top left. This TV display seems to have locked up and has to have power Off/On to get the display working again!

    I have searched and not found anyone with this problem!! I did try creating a display mode White List but that probably wont be active until after boot up!

    Chris.

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

    ^ You can append that to boot params in cmdline.txt and it will force initial resolution to 1920x1080 .. or perhaps 1280x720M@60 if it's an older set without FullHD resolutions.

    Great thanks for that! I knew there would be a setting somewhere to change the resolution at boot!

    However it does not cure the problem!

    In cmdline.txt :-

    boot=UUID=1507-5354 disk=UUID=077f401e-ddf6-42b9-95f9-dfb3c6c109f1 quiet

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

    Still boots 1366 X 768 X 62Hz according to the display setting popup!

    It works as long as I get to the display power button within about 5 seconds otherwise the screen locks up and needs power off restart!

    A 14year old HD Ready Samsung boots in 1280X720X60 but defaults to 1920x1080X50 although it only has 1366X788 display.

    A 10 year old Full HD Sharp TV displays nothing except the initial initial RPi multi colour screen flash! Has worked with RPi3 for many years!

    Chris

    Is this what you mean? This is a copy of the text used!

    In cmdline.txt :-

    boot=UUID=1507-5354 disk=UUID=077f401e-ddf6-42b9-95f9-dfb3c6c109f1 quiet video=HDMI-A-1:1920x1080M@60

    Its still using 1366x768x62HZ but none of my TVs can handle 62HZ

    Thanks for the help but it looks like the RPi4 has a fault and now defaults to 64Hz refresh!! Luckily I have an old RPi4 running TVHeadend server under LibreElec and that runs as it should when the same SD card is inserted!

    Thanks again Chris

    I think I was a bit hasty saying the new RPi4 was faulty. I have configured the mains so I can switch on the TV first and view the full boot sequence. Running 11.0.3 on one TV I am using to test bootup the first display frequency is 1080p 60Hz next 1366x786 62Hz for most of the boot sequence then 720p 50Hz which is the resolution in system settings! On this TV during the 62Hz time the display is torn and unreadable. In normal use with this RPi4 if this TV is not taken out of Standby within 5 seconds the screen locks up! Another TV displays nothing if this RPi4 is connected.

    However if I install version 11.0.1 all three TVs work as normal as there is no 1366x786 62Hz display mode!

    Chris

    Quote from jcjefferies

    I think I was a bit hasty saying the new RPi4 was faulty. I have configured the mains so I can switch on the TV first and view the full boot sequence. Running 11.0.3 on one TV I am using to test bootup the first display frequency is 1080p 60Hz next 1366x786 62Hz for most of the boot sequence then 720p 50Hz which is the resolution in system settings! On this TV during the 62Hz time the display is torn and unreadable. In normal use with this RPi4 if this TV is not taken out of Standby within 5 seconds the screen locks up! Another TV displays nothing if this RPi4 is connected.

    I'm not entirely understand the sequence of events here.

    For TV's that don't provide an EDID when powered off (many but not all do),

    you should power the TV on and select the correct AV input first.

    Assuming you have done this, then I'm not sure how this occurs:

    > In normal use with this RPi4 if this TV is not taken out of Standby within 5 seconds the screen locks up!

    So, does the TV behave as desired when it is powered on and switched to correct AV input before powering on the Pi?

    If yes, then then getedid create will make things much smoother in future (order of powering on won't matter).

    If no, then post a debug log.