I connected raspberry pi 3 to Official LCD 7 Inch display. When the HDMI is also connected i can see the Linux boot sequence on both screens. But when I unplugged the HDMI cable, i don't see any more the console on the LCD.
The image created by buildroot ( where all the tutorial out there are for Raspbiean)
I tried many things , all in config.txt
hdmi_group=2
hdmi_mode=1
hdmi_mode=87
hdmi_cvt=800 480 60 6 0 0 0
My target if to run QT5 app on the LCD , which does not work even. But I thought to ask this question first.
I don't mind using only the LCD , as primary solution or using both as dual screen. just need the LCD to work. Thanks!
To use QT in raspberry pi there are two options 1. Using Mesa vc4 driver 2. using rpi-userland
The problem is that mesa driver vc4 overlay have the problem where the console is not working if HDMI is not connected and QT5 does not start.
When using an image that has rpi-userland , we can see at boot time the four PI's on the top left corner and the 7 inch LCD will start show the boot sequence even if the HDMI is not connected. So don't use MESA driver use rpi-userland.
Once the image is built , all the steps to get QT working are valid and the apps ( QML) will work.