[mythtv-users] intermittent error starting mythfrontend on Raspberry PI OS 64 bit

[Jim Abernathy]

On 12/14/21 1:37 PM, Jim Abernathy wrote:
>
>
> On 12/14/21 11:57 AM, James Abernathy wrote:
>>
>>  I have tried to simplify the key part of the command from this:
>>
>> QT_QPA_EGLFS_ALWAYS_SET_MODE="1" QT_QPA_PLATFORM=eglfs 
>> QT_QPA_EGLFS_DEBUG=1 QT_LOGGING_RULES=qt.qpa.*=true 
>> QT_QPA_EGLFS_KMS_CONFIG=/home/pi/pi_mythfrontend.json mythfrontend 
>> $ARGUMENTS
>>
>> to this:
>>
>> QT_QPA_EGLFS_ALWAYS_SET_MODE="1" QT_QPA_PLATFORM=eglfs 
>> QT_QPA_EGLFS_DEBUG=1 QT_LOGGING_RULES=qt.qpa.*=true mythfrontend 
>> $ARGUMENTS
>>
>> It runs, but the CONFIG is defaulting to my UHD 4K parameters so the 
>> FPS jitter goes from +/-0.03 to  +/- 1.29. and the picture is no 
>> longer smooth. With the config it's supposed to make it 1080P. When 
>> it works it's great.
>>
>> Jim A
>>
>
> If I switch the RPI4 over to a 1080p FHD TV and just run:
>
> QT_QPA_EGLFS_ALWAYS_SET_MODE="1" QT_QPA_PLATFORM=eglfs mythfrontend
>
> It works fine with very good FPS jitter.  So the culprit seems to be 
> something is the way the QT_QPA_EGLFS_KMS_CONFIG=...json part of the 
> command is working to cause the error.
>
> Jim A
>

Here's what I found. The script that worked in Buster created a .json 
file that was used in the command and that file liked like this:

{
     "device": "/dev/dri/card1",
     "outputs": [
         { "name": "HDMI1", "mode": "1920x1080 at 60" }
     ]
}

Something changed in Bullseye that makes me have to change it to:

{
     "device": "/dev/dri/card1",
     "outputs": [
         { "name": "HDMI1", "mode": "1920x1080" }
     ]
}

Leaving off the @60 makes it work on a 4K UHD TV in 1080P mode. Checking 
the TV mode using the TV remote shows 1080p 60Hz.

Jim A


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