Cross-compile Qt5 for the Raspberry Pi
UPDATE
I’ve replaced the manual configuration (command line and scripts) described below with a more automated approach that relies on Buildroot for the creation of cross-compilation toolchain and target filesystem.
Introduction
Oftentimes when working on embedded projects it is not recommended (or not even possible) to develop directly on the target hardware, due to limitations of some sort. The Raspberry Pi, for example, does not offer a lot of computing power, which is why developing graphical interfaces on it is might be quite time consuming. A much more elegant, and ultimately faster, way of developing it is to write and build code on a host PC, then deploy the application to the (target) Raspberry Pi via a remote connection.
The workflow requires more steps and it might seem convoluted at first (it also requires to be kept up to date), but it is actually a better way to go about the whole development process.
There are two key aspects to cross-compiling:
- the toolchain, i.e. the set of tools (compiler, linker, etc.) available on the development machine (host) needed to build the source code into binary files for the embedded device (target).
- the target filesystem, i.e. the set of libraries and other relevant resources representing the target environment of the embedded device
TL;DR
The
Workflow
the steps below are a combination of all the old links (see above) I found but in the end mostly based on the https://github.com/abhiTronix/raspberry-pi-cross-compilers/blob/master/QT_build_instructions.md
Prepare Raspberry Pi
TODO: currently installed full system on SD but replace with download+chroot method
# 1. update raspberry
sudo apt-get update
sudo apt-get dist-upgrade
sudo reboot
sudo rpi-update
sudo reboot
# enable rsync sudo
echo "$USER ALL=NOPASSWD:$(which rsync)" | sudo tee --append /etc/sudoers
# 2. install development packages
sudo apt-get build-dep qt5-qmake
sudo apt-get build-dep libqt5gui5
sudo apt-get build-dep libqt5webengine-data
sudo apt-get build-dep libqt5webkit5
sudo apt-get install libudev-dev libinput-dev libts-dev libxcb-xinerama0-dev libxcb-xinerama0 gdbserver
# (optional, only for qtmultimedia)
sudo apt install libjpeg-dev libpng-dev libtiff-dev
sudo apt install libavcodec-dev libavformat-dev libswscale-dev libv4l-dev
sudo apt install libxvidcore-dev libx264-dev
# (optional) gstreamer (multimedia) packages
sudo apt install libgstreamer1.0-0 gstreamer1.0-plugins-base gstreamer1.0-plugins-good gstreamer1.0-plugins-bad gstreamer1.0-plugins-ugly gstreamer1.0-libav gstreamer1.0-doc gstreamer1.0-tools gstreamer1.0-x gstreamer1.0-alsa gstreamer1.0-gl gstreamer1.0-gtk3 gstreamer1.0-pulseaudio
sudo apt install libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev
# 3. create folder for Qt
sudo mkdir /usr/local/qt5.15
sudo chown -R pi:pi /usr/local/qt5.15
# 4. create symlinks
sudo ln -sf -r /usr/include/arm-linux-gnueabihf/asm /usr/include
sudo ln -sf -r /usr/include/arm-linux-gnueabihf/gnu /usr/include
sudo ln -sf -r /usr/include/arm-linux-gnueabihf/bits /usr/include
sudo ln -sf -r /usr/include/arm-linux-gnueabihf/sys /usr/include
sudo ln -sf -r /usr/include/arm-linux-gnueabihf/openssl /usr/include
sudo ln -sf /usr/lib/arm-linux-gnueabihf/crtn.o /usr/lib/crtn.o
sudo ln -sf /usr/lib/arm-linux-gnueabihf/crt1.o /usr/lib/crt1.o
sudo ln -sf /usr/lib/arm-linux-gnueabihf/crti.o /usr/lib/crti.o
# 5. (optional) setup ssh key folders, if not there (keys are copied over from PC later)
mkdir .ssh
cd .ssh
touch authorized_keys
chmod 700 ~/.ssh
chmod 600 ~/.ssh/authorized_keys
Prepare Host
# basic prep
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install gcc git bison python gperf pkg-config gdb-multiarch
###
# do keys /// alow root login without password..... https://raspberrypi.stackexchange.com/questions/48056/how-to-login-as-root-remotely
ssh-keygen -t rsa -C pi@ -P "" -f ~/.ssh/rpi_pi_id_rsa
cat ~/.ssh/rpi_pi_id_rsa.pub | ssh pi@192.168.1.172 'cat >> .ssh/authorized_keys && chmod 640 .ssh/authorized_keys'
# create dir
mkdir ~/qtrpi4
sudo mkdir ~/qtrpi4/tools
sudo mkdir ~/qtrpi4/build
sudo mkdir ~/qtrpi4/sysroot
sudo mkdir ~/qtrpi4/sysroot/usr
sudo mkdir ~/qtrpi4/sysroot/opt
sudo chown -R 1000:1000 ~/qtrpi4 # makes you own the folder
cd ~/qtrpi4
# sync stuff from raspy
rsync -avz --rsync-path="sudo rsync" --delete pi@192.168.1.172:/lib sysroot
rsync -avz --rsync-path="sudo rsync" --delete pi@192.168.1.172:/usr/include sysroot/usr
rsync -avz --rsync-path="sudo rsync" --delete pi@192.168.1.172:/usr/lib sysroot/usr
rsync -avz --rsync-path="sudo rsync" --delete pi@192.168.1.172:/opt/vc sysroot/opt
### download fix-symlink script (all sources are the same file)
#wget https://raw.githubusercontent.com/riscv/riscv-poky/master/scripts/sysroot-relativelinks.py
wget https://raw.githubusercontent.com/abhiTronix/rpi_rootfs/master/scripts/sysroot-relativelinks.py
sudo chmod +x sysroot-relativelinks.py
./sysroot-relativelinks.py sysroot
# download and config (a recent) compiler/toolchain
# https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/gnu-a/downloads
cd ~/qtrpi4/tools
#wget https://developer.arm.com/-/media/Files/downloads/gnu-a/10.3-2021.07/binrel/gcc-arm-10.3-2021.07-x86_64-arm-none-linux-gnueabihf.tar.xz
#tar xf gcc-arm-10.3-2021.07-x86_64-arm-none-linux-gnueabihf.tar.xz
wget https://sourceforge.net/projects/raspberry-pi-cross-compilers/files/Raspberry%20Pi%20GCC%20Cross-Compiler%20Toolchains/Buster/GCC%208.3.0/Raspberry%20Pi%203A%2B%2C%203B%2B%2C%204/cross-gcc-8.3.0-pi_3%2B.tar.gz
tar xf cross-gcc-*.tar.gz
cd ~/qtrpi4
### download and config qt
# TODO... change with clone repo and checkout branch
wget http://download.qt.io/archive/qt/5.15/5.15.2/single/qt-everywhere-src-5.15.2.tar.xz # -O qt-src.tar.xz
tar xf qt-everywhere-src-5.15.2.tar.xz
# adjust compiler
cp -R qt-everywhere-src-5.15.2/qtbase/mkspecs/linux-arm-gnueabi-g++ qt-everywhere-src-5.15.2/qtbase/mkspecs/linux-arm-gnueabihf-g++
sed -i -e 's/arm-linux-gnueabi-/arm-linux-gnueabihf-/g' qt-everywhere-src-5.15.2/qtbase/mkspecs/linux-arm-gnueabihf-g++/qmake.conf
# qt config
# https://doc.qt.io/qt-5/configure-linux-device.html
cd qtrpi4/build
../qt-everywhere-src-5.15.2/configure -release -opengl es2 -eglfs -device linux-rasp-pi4-v3d-g++ \
-device-option CROSS_COMPILE=~/qtrpi4/tools/cross-pi-gcc-8.3.0-2/bin/arm-linux-gnueabihf- \
-sysroot ~/qtrpi4/sysroot \
-prefix /usr/local/qt5.15 \
-extprefix ~/qtrpi4/qt5.15 \
-opensource -confirm-license -skip qtscript -skip qtwayland -skip qtwebengine -nomake tests -make libs -pkg-config -no-use-gold-linker -v -recheck \
-L$HOME/qtrpi4/sysroot/usr/lib/arm-linux-gnueabihf \
-I$HOME/qtrpi4/sysroot/usr/include/arm-linux-gnueabihf
make -j$(nproc)
make install
# NOTE 1
# -sysroot // this is where the rpi system is contained, on the PC
# -prefix // this is where the compiled qt will be copied to, on the RPI (the folder created in step3 of rpi preparation above)
# -extprefix // this is where the compiled qt is placed on the PC
# NOTE 2
# run "rm -rf *" before running config again
# qt deploy
cd ~/qtrpi4
rsync -avz --rsync-path="sudo rsync" --delete qt5.15 pi@192.168.1.172:/usr/local
Summary from CONFIGURE
Note that qt5 shall be configured after gstreamer 1.18.4 and opencv 4.5.3 installation
Building on: linux-g++ (x86_64, CPU features: mmx sse sse2)
Building for: devices/linux-rasp-pi4-v3d-g++ (arm, CPU features: neon)
Target compiler: gcc 10.3.1
Configuration: cross_compile compile_examples largefile neon precompile_header shared shared rpath release c++11 c++14 c++17 c++1z concurrent dbus reduce_exports stl
Build options:
Mode ................................... release
Optimize release build for size ........ no
Building shared libraries .............. yes
Using C standard ....................... C11
Using C++ standard ..................... C++17
Using ccache ........................... no
Using new DTAGS ........................ no
Relocatable ............................ yes
Using precompiled headers .............. yes
Using LTCG ............................. no
Target compiler supports:
NEON ................................. yes
Build parts ............................ libs
Qt modules and options:
Qt Concurrent .......................... yes
Qt D-Bus ............................... yes
Qt D-Bus directly linked to libdbus .... yes
Qt Gui ................................. yes
Qt Network ............................. yes
Qt Sql ................................. yes
Qt Testlib ............................. yes
Qt Widgets ............................. yes
Qt Xml ................................. yes
Support enabled for:
Using pkg-config ....................... yes
udev ................................... yes
Using system zlib ...................... yes
Zstandard support ...................... no
Qt Core:
DoubleConversion ....................... yes
Using system DoubleConversion ........ yes
GLib ................................... yes
iconv .................................. no
ICU .................................... yes
Built-in copy of the MIME database ..... yes
Tracing backend ........................ <none>
Logging backends:
journald ............................. no
syslog ............................... no
slog2 ................................ no
PCRE2 .................................. yes
Using system PCRE2 ................... yes
Qt Network:
getifaddrs() ........................... yes
IPv6 ifname ............................ yes
libproxy ............................... no
Linux AF_NETLINK ....................... yes
OpenSSL ................................ yes
Qt directly linked to OpenSSL ........ no
OpenSSL 1.1 ............................ yes
DTLS ................................... yes
OCSP-stapling .......................... yes
SCTP ................................... no
Use system proxies ..................... yes
GSSAPI ................................. no
Qt Gui:
Accessibility .......................... yes
FreeType ............................... yes
Using system FreeType ................ yes
HarfBuzz ............................... yes
Using system HarfBuzz ................ yes
Fontconfig ............................. yes
Image formats:
GIF .................................. yes
ICO .................................. yes
JPEG ................................. yes
Using system libjpeg ............... yes
PNG .................................. yes
Using system libpng ................ yes
Text formats:
HtmlParser ........................... yes
CssParser ............................ yes
OdfWriter ............................ yes
MarkdownReader ....................... yes
Using system libmd4c ............... no
MarkdownWriter ....................... yes
EGL .................................... yes
OpenVG ................................. no
OpenGL:
Desktop OpenGL ....................... no
OpenGL ES 2.0 ........................ yes
OpenGL ES 3.0 ........................ yes
OpenGL ES 3.1 ........................ yes
OpenGL ES 3.2 ........................ yes
Vulkan ................................. yes
Session Management ..................... yes
Features used by QPA backends:
evdev .................................. yes
libinput ............................... yes
INTEGRITY HID .......................... no
mtdev .................................. yes
tslib .................................. no
xkbcommon .............................. yes
X11 specific:
XLib ................................. yes
XCB Xlib ............................. yes
EGL on X11 ........................... yes
xkbcommon-x11 ........................ yes
QPA backends:
DirectFB ............................... no
EGLFS .................................. yes
EGLFS details:
EGLFS OpenWFD ........................ no
EGLFS i.Mx6 .......................... no
EGLFS i.Mx6 Wayland .................. no
EGLFS RCAR ........................... no
EGLFS EGLDevice ...................... yes
EGLFS GBM ............................ yes
EGLFS VSP2 ........................... no
EGLFS Mali ........................... no
EGLFS Raspberry Pi ................... no
EGLFS X11 ............................ yes
LinuxFB ................................ yes
VNC .................................... yes
Qt Sql:
SQL item models ........................ yes
Qt Widgets:
GTK+ ................................... no
Styles ................................. Fusion Windows
Qt PrintSupport:
CUPS ................................... yes
Qt Sql Drivers:
DB2 (IBM) .............................. no
InterBase .............................. no
MySql .................................. no
OCI (Oracle) ........................... no
ODBC ................................... yes
PostgreSQL ............................. yes
SQLite2 ................................ no
SQLite ................................. yes
Using system provided SQLite ......... no
TDS (Sybase) ........................... yes
Qt Testlib:
Tester for item models ................. yes
Serial Port:
ntddmodm ............................... no
Qt SerialBus:
Socket CAN ............................. yes
Socket CAN FD .......................... yes
SerialPort Support ..................... yes
Further Image Formats:
JasPer ................................. no
MNG .................................... no
TIFF ................................... yes
Using system libtiff ................. yes
WEBP ................................... yes
Using system libwebp ................. yes
Qt QML:
QML network support .................... yes
QML debugging and profiling support .... yes
QML just-in-time compiler .............. yes
QML sequence object .................... yes
QML XML http request ................... yes
QML Locale ............................. yes
Qt QML Models:
QML list model ......................... yes
QML delegate model ..................... yes
Qt Quick:
Direct3D 12 ............................ no
AnimatedImage item ..................... yes
Canvas item ............................ yes
Support for Qt Quick Designer .......... yes
Flipable item .......................... yes
GridView item .......................... yes
ListView item .......................... yes
TableView item ......................... yes
Path support ........................... yes
PathView item .......................... yes
Positioner items ....................... yes
Repeater item .......................... yes
ShaderEffect item ...................... yes
Sprite item ............................ yes
QtQuick3D:
Assimp ................................. yes
System Assimp .......................... no
Qt Scxml:
ECMAScript data model for QtScxml ...... yes
Qt Gamepad:
SDL2 ................................... no
Qt 3D:
Assimp ................................. yes
System Assimp .......................... no
Output Qt3D GL traces .................. no
Use SSE2 instructions .................. no
Use AVX2 instructions .................. no
Aspects:
Render aspect ........................ yes
Input aspect ......................... yes
Logic aspect ......................... yes
Animation aspect ..................... yes
Extras aspect ........................ yes
Qt 3D Renderers:
OpenGL Renderer ........................ yes
RHI Renderer ........................... no
Qt 3D GeometryLoaders:
Autodesk FBX ........................... no
Qt Bluetooth:
BlueZ .................................. no
BlueZ Low Energy ....................... no
Linux Crypto API ....................... no
Native Win32 Bluetooth ................. no
WinRT Bluetooth API (desktop & UWP) .... no
WinRT advanced bluetooth low energy API (desktop & UWP) . no
Qt Sensors:
sensorfw ............................... no
Qt Quick Controls 2:
Styles ................................. Default Fusion Imagine Material Universal
Qt Quick Templates 2:
Hover support .......................... yes
Multi-touch support .................... yes
Qt Positioning:
Gypsy GPS Daemon ....................... no
WinRT Geolocation API .................. no
Qt Location:
Qt.labs.location experimental QML plugin . yes
Geoservice plugins:
OpenStreetMap ........................ yes
HERE ................................. yes
Esri ................................. yes
Mapbox ............................... yes
MapboxGL ............................. yes
Itemsoverlay ......................... yes
QtXmlPatterns:
XML schema support ..................... yes
Qt Multimedia:
ALSA ................................... yes
GStreamer 1.0 .......................... yes
GStreamer 0.10 ......................... no
Video for Linux ........................ yes
OpenAL ................................. no
PulseAudio ............................. no
Resource Policy (libresourceqt5) ....... no
Windows Audio Services ................. no
DirectShow ............................. no
Windows Media Foundation ............... no
Qt TextToSpeech:
Flite .................................. no
Flite with ALSA ........................ no
Speech Dispatcher ...................... no
Qt Tools:
Qt Assistant ........................... yes
Qt Designer ............................ yes
Qt Distance Field Generator ............ yes
kmap2qmap .............................. yes
Qt Linguist ............................ yes
Mac Deployment Tool .................... no
makeqpf ................................ yes
pixeltool .............................. yes
qdbus .................................. yes
qev .................................... yes
Qt Attributions Scanner ................ yes
qtdiag ................................. yes
qtpaths ................................ yes
qtplugininfo ........................... yes
Windows deployment tool ................ no
WinRT Runner Tool ...................... no
Qt Tools:
QDoc ................................... yes
Note: Also available for Linux: linux-clang linux-icc
Note: PKG_CONFIG_LIBDIR automatically set to /home/stefano/qtrpi4/sysroot/usr/lib/pkgconfig:/home/stefano/qtrpi4/sysroot/usr/share/pkgconfig:/home/stefano/qtrpi4/sysroot/usr/lib/arm-linux-gnueabihf/pkgconfig
Note: PKG_CONFIG_SYSROOT_DIR automatically set to /home/stefano/qtrpi4/sysroot
Qt is now configured for building. Just run 'make'.
Once everything is built, you must run 'make install'.
Qt will be installed into '/home/stefano/qtrpi4/qt5.15'.
Prior to reconfiguration, make sure you remove any leftovers from
the previous build.
Finalize Raspberry Pi setup
echo /usr/local/qt5.15/lib | sudo tee /etc/ld.so.conf.d/qt5.15.conf
sudo ldconfig
Configure QtCreator
On the host computer.
following https://www.interelectronix.com/configuring-qt-creator-ubuntu-20-lts-cross-compilation.html
adding debugger https://www.youtube.com/watch?v=1d2bh7iUKNc&list=PLFsidzAJDEbBr3l0BNMDcDQlUM04GRlf2
Configure Qt project
deploy applications (official) - https://doc.qt.io/qtcreator/creator-deployment-embedded-linux.html
https://www.ics.com/blog/configuring-qt-creator-raspberry-pi
add this to the .pro file
target.path = /home/pi/
INSTALLS += target
Troubleshooting
Fine tune EGLFS
(official) https://doc.qt.io/qt-5/embedded-linux.html
https://forum.qt.io/topic/84827/qt5-eglfs-screen-resolutio
QT_QPA_EGLFS_PHYSICAL_WIDTH =
QT_QPA_EGLFS_PHYSICAL_HEIGHT =
IMPORTANT!!! For correct scaling and dimensions remove any DPI scaling from the main.cpp (see below)
QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
Error(s) related to DRM
Could not queue DRM page flip on screen on RaspberryPi
Could not queue DRM page flip on screen HDMI
https://forums.raspberrypi.com/viewtopic.php?t=252614 // this explains for example that when X is running no other app can attach
https://github.com/UvinduW/Cross-Compiling-Qt-for-Raspberry-Pi-4/issues/10
# add this line to .profile file on RPi
QT_QPA_EGLFS_ALWAYS_SET_MODE=1
Testing
- TODO: test hardware acceleration
External Resources
QT5 Cross compile GUI with buildroot for raspberry pi3
buildroot qt5 32bit mesa opengl on raspberry pi 3
https://github.com/pbouda/buildroot-qt-dev/tree/master/config
Cross-compile Qt applications for your Raspberry Pi 3 - 1. Install QtRpi from scratch
Cross-compile Qt applications for your Raspberry Pi 3 - 2. Configure Qt Creator
About filesystem
have a look here to automate stuff even more https://github.com/abhiTronix/rpi_rootfs
About toolchains
https://github.com/Pro/raspi-toolchain/
original - https://www.kampis-elektroecke.de/raspberry-pi/qt/
interelectronix (working till a certain steps but uses too old compiler)- https://www.interelectronix.com/qt-on-the-raspberry-pi-4.html
uvinduw (another that is ALMOST working) - https://github.com/UvinduW/Cross-Compiling-Qt-for-Raspberry-Pi-4
interelectronix - QtCreator (ok, ut doesn’t show then how to start a project, which will fail of course) - https://www.interelectronix.com/configuring-qt-creator-ubuntu-20-lts-cross-compilation.html
neuralmotion qtrpi - https://github.com/neuronalmotion/qtrpi
mechatronicsblog - https://mechatronicsblog.com/cross-compile-and-deploy-qt-5-12-for-raspberry-pi/
https://www.youtube.com/watch?v=5SnXJTwIunY
https://medium.com/@au42/the-useful-raspberrypi-cross-compile-guide-ea56054de187
[https://github.com/Pro/raspi-toolchain]
