[PROBLEM] HDMI output shows no terminal but only black screen after moOde installation

[deztiny]

Hello everybody,
perhaps someone has an idea how to solve this topic. I have been already in PM contact with Tim, he does not have an idea and no priority for this topic since he is only using SSH.
So perhaps there is someone out there who has a clue about Linux/Raspbian and how to make it work?

Description:
When writing Raspian Image and booting, HDMI output and directly attached official 7" Touch Display is showing terminal with login prompt ("raspberrypi login:").
After moOde installation (via mosbuild), directly attached official 7" Touch Display is still showing terminal with login prompt ("moode login:") but HDMI output is only showing black screen. Still HDMI output is showing startup commands and shutdown commands. But after startup, exactly at the moment when termin would be showing login prompt the screen goes black. Plus there is a signal (my monitor does not switch to standby) but the signal that is on is "only black".
I tried to deactivate and activate HDMI output in moOde settings but it does not help.
I guess it is some kind of Linux/Raspbian setting that gets activated in the process of mosbuild?

Thank you for your help!
Mario

[JST1963]

Hi moOde fans,

[deztiny]

I connected two or three computer monitors, native is FullHD meaning 1920x1080. And they never complained about an incompatible resolution. They are behaving like everything is fine - a signal is there it is just nothing else than "black".

[deztiny]

I found somehing that describes it very well - but I dont have a clue about Linux and how to handle it:
"Essentially, the setterm -blank 0 command sets the terminal blanking period to 0 seconds (off), disabling the blanking which usually occurs. rc.local is executed at the end of the boot process with root privileges so it affects all the physical consoles (the TV & HDMI outputs here)"

Found at: https://raspberrypi.stackexchange.com/qu...od-of-time

But I guess mosbuild does not set this parameter?

[Koda59]

Hi deztiny,

I think that the main reason is because during building operation via /etc/rc.local, we don't let the boot process finished (no ampersand on mosbuild entry in /etc/rc.local), so boot will never be complete (can't go until exit 0 line in /etc/rc.local) until mosbuild completed all tasks.

During installation process, do you really need that ?

If so and you really want to investigate, try to change line 517 mosbuild.sh :

echo "$MOSBUILD_DIR/mosbuild_worker.sh >> /home/pi/mosbuild.log 2>> /home/pi/mosbuild.log" >> part2/etc/rc.local

by

echo "$MOSBUILD_DIR/mosbuild_worker.sh >> /home/pi/mosbuild.log 2>> /home/pi/mosbuild.log &" >> part2/etc/rc.local

In that case, the rc.local will finished and boot process will be complete so i hope you will retrieve your screen  

I think this is the same thing for all the day use  :

Maybe try to change /etc/rc.local and add ampersand on worker.php line like this :

/var/www/command/worker.php > /dev/null 2>&1 &

Regards

[deztiny]

Hello Koda59,
thanks for your reply. Really don't need HDMI output during installation process, but it would be very nice if it would be working (again) after installation process.
So I was curious why HDMI output is not working after installation process anymore.

Regards

[Tim Curtis]

Try this key sequence

Ctrl-Alt-1 -OR- Ctrl-Alt-F1

[deztiny]

Ctrl-Alt-1 is causing a reaction during bootup but does not help when the screen shows black.

During boot it causes a grey blank screen with three dots in the middle of the screen. Then the "moode login:" is displayed on the upper left corner and then the screen goes black again. So it looks like a command is causing black output after bootup is finished.

[Tim Curtis]

I'm using a Logitech K400R trackpad keyboard and the key sequence Alt+FN+F2 activates the login prompt. Internally its assigned to tty2. I think the missing login prompt is a result of some sort of conflict with the Systemd configuration for tty1 but I'm not really sure how to isolate this one.

-Tim

[deztiny]

Great, this workaround works! ;-)
Pressing Alt+F1 right from the start does NOT work.
But pressing Alt+F2 is showing a fresh terminal with login and THEN pressing Alt+F1 is showing the regular bootup sequence stats including login.
Thanks a lot!

If there is a Linux Pro who is curious or interested in finding out what causes the switch to black signal in the first place, feel free to let us know...