Overview

The Buildroot route compiles Qt5 as part of the root filesystem, producing a minimal Linux image that includes the Qt runtime libraries:

• Lightweight: No desktop environment; all system resources are reserved for the application
• Full-screen eglfs: Qt applications drive the display directly via KMS/DRM, bypassing X11/Wayland
• Integrated: Qt libraries, toolchain, and kernel image are managed within the same build system, ensuring version consistency

SDK path: /home/lckfb/TaishanPi-3-Linux Qt version: 5.15.11 (defined by buildroot/package/qt5/qt5.mk)

Prerequisites

1. Dependency installation completed per Environment Setup
2. Host meets minimum build requirements: 8-core CPU, 16 GB RAM, 150 GB available storage

Enabling Qt5 in Buildroot

Entering menuconfig

# Enter the SDK root directory
cd /home/lckfb/TaishanPi-3-Linux

# Interactive selection (recommended)
./build.sh lunch
# Select tspi_3m_rk3576_buildroot_defconfig

# Directly open menuconfig
./build.sh bconfig

bconfig opens the Buildroot menuconfig interface. After saving, it automatically updates the default configuration file (buildroot/configs/rockchip_rk3576_defconfig).

Key Configuration Items

For the complete module list, refer to Buildroot Qt5 Module Configuration Reference

In menuconfig, navigate to: Target packages → Graphic libraries and applications (graphic/text) → Qt5

Configuration Item	Description	Required
BR2_PACKAGE_QT5	Qt5 master switch	Required
BR2_PACKAGE_QT5BASE	Qt5 core libraries (QtCore/Network/Gui, etc.)	Required
BR2_PACKAGE_QT5BASE_FONTCONFIG	Fontconfig font management	Required
BR2_PACKAGE_QT5BASE_GUI	GUI module	Required
BR2_PACKAGE_QT5BASE_WIDGETS	Widgets module	Required
BR2_PACKAGE_QT5BASE_OPENGL	OpenGL support	Required
BR2_PACKAGE_QT5BASE_EGLFS	eglfs backend (required for full-screen apps)	Required
BR2_PACKAGE_QT5BASE_DEFAULT_QPA	Set to eglfs	Required
BR2_PACKAGE_NFS_UTILS	NFS utilities	Optional
BR2_PACKAGE_QT5BASE_LINUXFB	linuxfb backend (fallback, usable without GPU)	Optional
BR2_PACKAGE_QT5DECLARATIVE	QML support	As needed
BR2_PACKAGE_QT5QUICKCONTROLS2	Quick Controls 2	As needed
BR2_PACKAGE_QT5SVG	SVG support	As needed
BR2_PACKAGE_QT5MULTIMEDIA	Multimedia support	As needed

It is recommended to also enable the NFS client

The subsequent Communication Channels Configuration recommends using NFS for development iteration. To avoid having to recompile later, it is recommended to enable it at this stage:

Target packages → Networking applications → nfs-utils (check BR2_PACKAGE_NFS_UTILS)

The eglfs_kms backend depends on the Mali GPU driver. Ensure the following is also enabled:

Target packages → Hardware handling → Firmware → rockchip-mali
  → BR2_PACKAGE_ROCKCHIP_MALI=y

Compiling Qt5

Full Build (Recommended for First Use)

cd /home/lckfb/TaishanPi-3-Linux
./build.sh all

Building Qt5 Package Individually

# First-time Qt5 build
./build.sh bmake:qt5base

# Force rebuild (use after modifying configuration)
./build.sh bmake:qt5base-rebuild

Build Output

After compilation, build artifacts are located under buildroot/output/rockchip_rk3576/:

Path	Contents
host/bin/qmake	qmake for cross-compilation
host/bin/	Qt host tools (moc, rcc, uic, etc.) and Buildroot cross-compiler
host/share/buildroot/toolchainfile.cmake	Buildroot auto-generated CMake toolchain file
staging/usr/include/qt5/	Qt5 header files
staging/usr/lib/libQt5*.so	Qt5 shared libraries (for linking)
staging/usr/lib/cmake/	Qt5 CMake configuration files
target/usr/lib/libQt5*.so	Qt5 runtime libraries deployed to the board

staging/ is a symlink to host/aarch64-buildroot-linux-gnu/sysroot/, which is the cross-compiler's sysroot directory. The contents of target/ are packaged into the root filesystem image.

You must re-flash after compilation

If the board is currently running an image that does not include Qt runtime libraries, you must flash the newly compiled image to the development board. Skipping this step will cause Qt programs to fail to start due to missing runtime libraries. See System Flashing for flashing instructions.

Next Step

After compilation is complete, flash the new image to the development board (see System Flashing), then configure the Communication Channels.