Guide - cross-compile Qt for Raspberry Pi 3

Cross-compile Qt-Rpi3 教學
Qt ver. 5.10.1
Raspbian 2018-04-18-Stretch
Ubuntu ver. 16.04

Reference

Official Guide

Other Guide

Preparation

[硬體]

  • PC x1
  • Raspberry Pi x1
  • 5v 2A 電源 for RPi x1
  • USB to TTL x1
  • HDMI or HDMI to VGA cable x1
  • Touchscreen (Inculde power) x1

[OS] RASPBIAN 下載 Full版 IMAGE 舊版的 or 最新版. 然後燒錄至SD Card. (@Lite版沒測試過，有看到成功案例)

Ubuntu 下載 16.04

如果在Windows底下可以用虛擬機器 (Victualbox) 最好先掛好共享資料夾 ，Guest Additions 經常掛載失敗，需額外安裝元件

sudo apt-get install virtualbox-guest-dkms

sudo mount -t vboxsf <共享資料夾名稱> <掛載目的地資料夾路徑>
Ex: sudo mount -t vboxsf Download /home/hung/文件/data

Step by step

Prepare Raspberry Pi

[on RPi] 裝上SDCard ,網路線 ,USB to TTL ,插電

[on RPi] Edit sources list in /etc/apt/sources.list and uncomment the deb-src line

sudo nano /etc/apt/sources.list

uncomment = 拿掉下面這行的#字符號

#deb-src http://raspbian.raspberrypi.org/raspbian/ stretch main contrib non-free rpi

[on RPi] (optional) 執行 raspi-config :

  1. Change it to boot to the console instead of X.
  2. Change the GPU memory to 256 MB.

    切記不要開啟Hardware Acceleration功能，推估需編譯 pi3-vc4版本，才能正常使用

sudo raspi-config

[on RPi] 系統更新

sudo apt-get update
sudo apt-get dist-upgrade
sudo reboot

[on RPi] 韌體更新 (額外要注意的BUG)，後續會手動處理symlinks，可忽略。

sudo rpi-update
sudo reboot

[on RPi] (optional)安裝遠端連線，方便測試 (相關教學)

$ sudo apt-get install xrdp

[on RPi] Install dependencies

sudo apt-get build-dep qt4-x11
sudo apt-get build-dep libqt5gui5
sudo apt-get install libudev-dev libinput-dev libts-dev libxcb-xinerama0-dev libxcb-xinerama0

If you are interested in Bluetooth support then:

sudo apt-get install bluetooth bluez libbluetooth-dev bluez-tools

[on RPi] Prepare our target directory

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

If ready, dont shutdown your raspberry pi!~

Prepare Linux host

[on host PC] Update

sudo apt-get update
sudo apt-get -y upgrade

[on host PC] Install dependencies

sudo apt-get install git bison python gperf

[on host PC] Installing QT Creator 5.10.1 on your Linux . ( 官網下載 )

[on host PC] Generate ssh public key

ssh-keygen -t rsa -C pi@raspberrypi.local -N "" -f ~/.ssh/id_rsa

cat ~/.ssh/id_rsa.pub | ssh -o StrictHostKeyChecking=no pi@raspberrypi.local "mkdir -p .ssh && chmod 700 .ssh && cat >> .ssh/authorized_keys"

[on host PC] Create our working directory:

mkdir ~/raspi
cd ~/raspi

[on host PC] Get a toolchain:

git clone https://github.com/raspberrypi/tools

Add toolchain binary directory to PATH. Open .bashrc and add line at end of file

nano ~/.bashrc

把下面這行加入到.bashrc這個文件的最下面

export PATH=$PATH:/home/pi/raspi/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin

To activate this changes, you have to restart the terminal. If you use a 32Bit host, use this toolchain path: /raspi/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin

用which測試你的環境變數是否正確載入Toolchan位置

 which arm-linux-gnueabihf-gcc

Sync Raspberry Pi

[on host PC] Create a sysroot. Using rsync we can properly keep things synchronized in the future as well. Replace raspberrypi.local with the IP address of the Pi.

mkdir sysroot sysroot/usr sysroot/opt
rsync -avz pi@raspberrypi.local:/lib sysroot
rsync -avz pi@raspberrypi.local:/usr/include sysroot/usr
rsync -avz pi@raspberrypi.local:/usr/lib sysroot/usr
rsync -avz pi@raspberrypi.local:/opt/vc sysroot/opt

同步上可能會遇到權限不足的問題，可透過sudo + chmod 來強制完成可以同步的部分。

[on host PC] Create correct symlinks to “missing” libraries

mv sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so.1.0.0 sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so.1.0.0_backup
ln -s sysroot/opt/vc/lib/libEGL.so sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so.1.0.0

mv sysroot/usr/lib/arm-linux-gnueabihf/libGLESv2.so.2.0.0 sysroot/usr/lib/arm-linux-gnueabihf/libGLESv2.so.2.0.0_backup
ln -s sysroot/opt/vc/lib/libGLESv2.so sysroot/usr/lib/arm-linux-gnueabihf/libGLESv2.so.2.0.0

ln -s sysroot/opt/vc/lib/libEGL.so sysroot/opt/vc/lib/libEGL.so.1

ln -s sysroot/opt/vc/lib/libGLESv2.so sysroot/opt/vc/lib/libGLESv2.so.2

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

wget https://raw.githubusercontent.com/riscv/riscv-poky/priv-1.10/scripts/sysroot-relativelinks.py
chmod +x sysroot-relativelinks.py
./sysroot-relativelinks.py sysroot

Compiler Qt Source

Get qtbase and configure Qt. The target directory is /usr/local/qt5pi on the Pi, the host tools like qmake will go to ~/raspi/qt5, while make install will target ~/raspi/qt5pi (this is what we will sync to the device). Don’t forget to adjust paths if you changed that. For some reason the ~/ in the paths may not work, if this the case just use full paths.

You need to change < qt-version> with a proper Qt version (for example 5.6, or 5.9.1; note that version 5.9.1 is a tag not a branch, so you may want to create a local branch with it)

You need to change < rpi-version> with a proper Raspberry Pi version. Use: linux-rasp-pi-g++ for RPi, linux-rasp-pi2-g++ for RPi2 and linux-rasp-pi3-g++ for RPi3.

[on host PC] Get Qt sources and untar Qt sources

wget https://download.qt.io/official_releases/qt/5.10/5.10.1/single/qt-everywhere-src-5.10.1.tar.xz

tar xf qt-everywhere-src-5.10.1.tar.xz

[on host PC] Create hf configuration

cp -r qt-everywhere-src-5.10.1/qtbase/mkspecs/linux-arm-gnueabi-g++ qt-everywhere-src-5.10.1/qtbase/mkspecs/linux-arm-gnueabihf-g++
sed -i -e 's/arm-linux-gnueabi-/arm-linux-gnueabihf-/g' qt-everywhere-src-5.10.1/qtbase/mkspecs/linux-arm-gnueabihf-g++/qmake.conf

[on host PC] Create build dir and configure source 如果後續make有問題或要重編，直接砍掉qt5buid就好‧

mkdir qt5build
cd qt5build

../qt-everywhere-src-5.10.1/configure -opengl es2 -device linux-rasp-pi3-g++ -device-option CROSS_COMPILE=arm-linux-gnueabihf- -sysroot ~/raspi/sysroot -prefix /usr/local/qt5pi -opensource -confirm-license -nomake examples -make libs -no-use-gold-linker -no-icu -skip qtwebengine -skip wayland -skip qtscript -v

Sadly QtWebengine dont compile on Raspberry Pi 1 (maybe also Pi 2), so we have to skip it. Also skip QtScript, its deprecated.

[on host PC]Make

make
make install

恭喜您突破第一道難關~

Upload to raspberry pi

[on host PC]Upload to raspberry pi

cd ~/raspi
rsync -avz sysroot/usr/local/qt5pi pi@raspberrypi.local:/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

[on RPi]Fix the EGL/GLES libraries. The device may have the Mesa version of libEGL and libGLESv2 in /usr/lib/arm-linux-gnueabihf, resulting Qt apps picking these instead of the real thing from /opt/vc/lib. This may be fine for X11 desktop apps not caring about OpenGL performance but is totally useless for windowing system-less, fullscreen embedded apps. You may want to save the originals somewhere, just in case. Make sure you’re in “/home/pi” aka “~” when you run these commands:

sudo mv /usr/lib/arm-linux-gnueabihf/libEGL.so.1.0.0 /usr/lib/arm-linux-gnueabihf/libEGL.so.1.0.0_backup
sudo mv /usr/lib/arm-linux-gnueabihf/libGLESv2.so.2.0.0 /usr/lib/arm-linux-gnueabihf/libGLESv2.so.2.0.0_backup
sudo ln -s /opt/vc/lib/libEGL.so /usr/lib/arm-linux-gnueabihf/libEGL.so.1.0.0
sudo ln -s /opt/vc/lib/libGLESv2.so /usr/lib/arm-linux-gnueabihf/libGLESv2.so.2.0.0

Please make sure to also add missing symbolic links:

sudo ln -s /opt/vc/lib/libEGL.so /opt/vc/lib/libEGL.so.1
sudo ln -s /opt/vc/lib/libGLESv2.so /opt/vc/lib/libGLESv2.so.2

Qt configuration

Tools->Options…->Devices->Add Generic Linux Device Edit Hostname, authentication type key, username and add private key ( ~/.ssh/id_rsa )

Tools->Options…->Kits->Debuggers->Add Edit name and path

 ~/raspi/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin/arm-linux-gnueabihf-gdb

Tools->Options…->Kits->Compilers->Add->GCC->C Edit name and path

~/raspi/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin/arm-linux-gnueabihf-gcc

Tools->Options…->Kits->Compilers->Add->GCC->C++ Edit name and path

~/raspi/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin/arm-linux-gnueabihf-g++

Tools->Options…->Kits->Qt Versions->Add Choose

~/raspi/sysroot/usr/local/qt5pi/bin/qmake

Tools->Options…->Kits->Kits->Add Edit name

Device type: Generic Linux Device
Device: Choose prior created raspberry pi device
Sysroot: Choose ~/raspi/sysroot
C and C++: Choose prior created raspberry pi compilers
Debugger: Choose prior created raspberry pi debugger
Qt version: Choose prior created raspberry pi qt version
PREVIOUSRemote debugging on the Raspberry PI from Qt