Cross-Compile QT 5.15.1 / Raspberry Pi 4

Running Raspbian Buster on Raspberry Pi 4:

[on RPi] Install a bunch of development files (for simplicity we use build-dep, not everything is really needed, but it is easier this way).

Edit sources list in /etc/apt/sources.list and uncomment the deb-src line:

sudo nano /etc/apt/sources.list

Update your system and install required libraries:

sudo apt-get update
sudo apt-get build-dep qt5-default
sudo apt-get install libegl1-mesa libegl1-mesa-dev libgles2-mesa libgles2-mesa-dev libgbm-dev mesa-common-dev

Optional depending on your project:

sudo apt-get install wiringpi libnfc-bin libnfc-dev fonts-texgyre libts-dev

Optional depending if you want to use QtMultimedia:

sudo apt-get install libbluetooth-dev bluez-tools gstreamer1.0-plugins* libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev libopenal-data libsndio7.0 libopenal1 libopenal-dev pulseaudio

[on RPi] Add pi user to render group

sudo gpasswd -a pi render

[on RPi] Prepare our target directory

sudo mkdir /usr/local/qt5pi
sudo chown pi:pi /usr/local/qt5pi

[on host] Create our working directory and get a toolchain:

mkdir ~/raspi
cd ~/raspi
wget https://releases.linaro.org/components/toolchain/binaries/latest-7/arm-linux-gnueabihf/gcc-linaro-7.5.0-2019.12-x86_64_arm-linux-gnueabihf.tar.xz
tar -xvf gcc-linaro-7.5.0-2019.12-x86_64_arm-linux-gnueabihf.tar.xz

[on host] Create a sysroot. Using rsync we can properly keep things synchronized in the future as well.

mkdir sysroot sysroot/usr sysroot/opt
rsync -avz pi@yourpi:/lib sysroot
rsync -avz pi@yourpi:/usr/include sysroot/usr
rsync -avz pi@yourpi:/usr/lib sysroot/usr
rsync -avz pi@$yourpi:/opt/vc sysroot/opt

[on host] Adjust symlinks to be relative. Use provided script, because the old fixQualifiedLibraryPaths is not working properly:

wget https://raw.githubusercontent.com/riscv/riscv-poky/master/scripts/sysroot-relativelinks.py
chmod +x sysroot-relativelinks.py
./sysroot-relativelinks.py sysroot

[on host] Get QT (start with qtbase first)

git clone git://code.qt.io/qt/qtbase.git -b 5.15.1
cd qtbase

[on host] Compile, make, make install

./configure -release -opengl es2 -device linux-rasp-pi4-v3d-g++ -device-option CROSS_COMPILE=~/$build_dir/gcc-linaro-7.5.0-2019.12-x86_64_arm-linux-gnueabihf/bin/arm-linux-gnueabihf- -sysroot ~/$build_dir/sysroot -opensource -confirm-license -make libs -prefix /usr/local/qt5pi -extprefix ~/$build_dir/qt5pi -hostprefix ~/$build_dir/qt5 -v
make -j4
make install

If you failed build –>

git clean -dfx

[on host] Deploy Qt to the device. We simply sync everything from ~/raspi/qt5pi to the prefix we configured above.

rsync -avz qt5pi pi@yourpi:/usr/local

[on RPi] Update the device to let the linker find the Qt libs:

echo /usr/local/qt5pi/lib | sudo tee /etc/ld.so.conf.d/qt5pi.conf
sudo ldconfig

git clone git://code.qt.io/qt/<qt-module>.git -b <qt-version>
cd <qt-module>

~/raspi/qt5/bin/qmake

make 
make install

rsync -avz qt5pi pi@yourpi:/usr/local

Set physical Display size in mm:

sudo nano ~/.profile

# physical display properties
export QT_QPA_EGLFS_PHYSICAL_WIDTH=211
export QT_QPA_EGLFS_PHYSICAL_HEIGHT=127

source .profile

Workarounds:

Fehlermeldung:

Could not queue DRM page flip on screen DSI1

export QT_QPA_EGLFS_ALWAYS_SET_MODE="1"

Bluetooth Service startet nicht:

sudo nano /etc/systemd/system/bluetooth.target.wants/bluetooth.service

Change:

ExecStart=/usr/lib/bluetooth/bluetoothd --noplugin=sap

Berechtigungen setzen für Bluetooth:

sudo setcap 'cap_net_raw,cap_net_admin+eip' /path/to/your/application