No Screen but Web interface

[vicat56]

Hello everyone,

i tried to install using the qlcplus_raspios_bookworm_20240907 image QLC on a Raspberry pi 4 with a 64 gb micro SD (don't have less...)

I have an HDMI monitor plugged in (1080p 144hz monitor, locked here at 60hz)
i tried a VGA monitor (via cheap converter)

i have this error when i look at the status of qlc :

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pi@raspberrypi:~ $ sudo service qlcplus status
● qlcplus.service - Q Light Controller Plus
     Loaded: loaded (/lib/systemd/system/qlcplus.service; enabled; preset: enabled)
     Active: active (running) since Fri 2024-09-13 19:05:33 BST; 1min 34s ago
       Docs: man:qlcplus(1)
   Main PID: 548 (bash)
      Tasks: 9 (limit: 3917)
        CPU: 2.199s
     CGroup: /system.slice/qlcplus.service
             ├─548 bash /usr/sbin/qlcplus-start.sh
             └─635 /usr/bin/qlcplus -platform offscreen --nowm --web --web-auth --operate --overscan

We can see that the status is "-platform offscreen", so i believe that the raspberry don't detect the screen, but the soft is working.

if i

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sudo service qlcplus restart

, it show up !


What can i do to fix that ?


Thank you !

[mcallegari]

At the beginning of the startup script there is a check for a connected display
https://github.com/mcallegari/qlcplus/b ... art.sh#L22
if that fails QLC+ starts without an actual output.

I'd say your display is slow to be detected (or sleeping?) so you'd need to delay the systemd script to a later stage of the boot sequence (e.g. after network)
Or brutally place a sleep command before the check above.

[vicat56]

Hello, thanks for your help, i will try to delay that !

Btw, i think that you are right with the "slow" monitor thnig, because i tried this morning and i needed to start the screen a few second before the raspi to change manualy the video input, and now it works....! I dig a bit further

thank you again

[markzvo]

I have seen this behavior as well, some boots do not work properly because the display is not yet detected... I will probably have to add sleep 3 to /usr/sbin/qlcplus-start.sh file before the HDMI detection logic

[vicat56]

great idea !
thank you

[Peetem]

I have seen this behavior as well, some boots do not work properly because the display is not yet detected... I will probably have to add sleep 3 to /usr/sbin/qlcplus-start.sh file before the HDMI detection logic

Did this work? How was it done?

Still can't get mine to recognize the display....

[markzvo]

I have a Pi 5 with NVMe storage so my setup is VERY fast... so I only saw this issue once. But no more after Sleep 3.

Try Sleep 20? Anything longer than that and you may have a different issue such as a display that is not Linux-friendly.

[tdunlop]

Has there been any resolution to this problem? I'm having the same issue on a pi4 4GB. No web interface and no screen on the latest image (20241101). I tried rolling back to an earlier image (20230519) and was able to get the web interface working but had no screen. I tried making adjustments to /usr/sbin/qlcplus-start.sh but no luck. I'm more than willing to tinker with things, so if you have any suggestions I'm all ears.

[mcallegari]

Has there been any resolution to this problem? I'm having the same issue on a pi4 4GB. No web interface and no screen on the latest image (20241101). I tried rolling back to an earlier image (20230519) and was able to get the web interface working but had no screen. I tried making adjustments to /usr/sbin/qlcplus-start.sh but no luck. I'm more than willing to tinker with things, so if you have any suggestions I'm all ears.

Might be the same of this?
https://www.qlcplus.org/forum/viewtopic.php?t=17877
Are you customizing the image when flashing it?

[vicat56]

I have seen this behavior as well, some boots do not work properly because the display is not yet detected... I will probably have to add sleep 3 to /usr/sbin/qlcplus-start.sh file before the HDMI detection logic

Did this work? How was it done?

Still can't get mine to recognize the display....

I'm a bit late... Yes the issue was my "slow" screen. so a timer was the way to go for me.

[stockers]

I am seeing similar problems, using the latest release, a PI 5 with an official raspberry PI touch screen (original). I have set the delay to both 3 and 20.
1 time out of every 5 to 10, it will start properly with the screen displaying properly. the rest of the time, it shows the command prompt and does not start QLC. disconnecting and reconnecting the power a number of times eventually resolvesthe issue.

If I add the line QTPLATFORM="linuxfb" after the autodetect in qlcplus-start.sh, it works every time, but the screen is not usable (wrong fonts and sizes for tabs, etc.). If i manually set it to "eglfs" (i.e. bypass the detection and force a screen) I get the same unreliable startup.

Not sure what is going on as I make no changes between it working and failing...