How to configure Qt with enabled udev support?

[MHermann]

Hi all,

I want to build Qt5.9 with udev support for raspberry pi.
At the moment I try to configure the Qt.

My problem is that support for udev is disabled and I don't know how I can enable this.
Does anyone know how I can enable the udev support?

This is the output I get:

Mode ................................... release; optimized tools
  Optimize release build for size ........ no
  Building shared libraries .............. yes
  Using C++ standard ..................... C++11
  Using gold linker ...................... yes
  Using new DTAGS ........................ yes
  Using precompiled headers .............. yes
  Using LTCG ............................. no
  Target compiler supports:
    NEON ................................. no
  Build parts ............................ libs
Qt modules and options:
  Qt Concurrent .......................... yes
  Qt D-Bus ............................... yes
  Qt D-Bus directly linked to libdbus .... no
  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
  QML debugging .......................... yes
  udev ................................... no
  Using system zlib ...................... yes
Qt Core:
  DoubleConversion ....................... yes
    Using system DoubleConversion ........ no
  GLib ................................... no
  iconv .................................. yes
  ICU .................................... no
  Logging backends:
    journald ............................. no
    syslog ............................... no
    slog2 ................................ no
  Using system PCRE2 ..................... no
Qt Network:
  getaddrinfo() .......................... yes
  getifaddrs() ........................... yes
  IPv6 ifname ............................ yes
  libproxy ............................... no
  OpenSSL ................................ no
    Qt directly linked to OpenSSL ........ no
  SCTP ................................... no
  Use system proxies ..................... yes
Qt Gui:
  Accessibility .......................... yes
  FreeType ............................... yes
    Using system FreeType ................ yes
  HarfBuzz ............................... yes
    Using system HarfBuzz ................ no
  Fontconfig ............................. no
  Image formats:
    GIF .................................. yes
    ICO .................................. yes
    JPEG ................................. yes
      Using system libjpeg ............... no
    PNG .................................. yes
      Using system libpng ................ yes
  EGL .................................... yes
  OpenVG ................................. yes
  OpenGL:
    Desktop OpenGL ....................... no
    OpenGL ES 2.0 ........................ yes
    OpenGL ES 3.0 ........................ no
    OpenGL ES 3.1 ........................ no
  Session Management ..................... yes
Features used by QPA backends:
  evdev .................................. yes
  libinput ............................... no
  INTEGRITY HID .......................... no
  mtdev .................................. no
  tslib .................................. no
  xkbcommon-evdev ........................ no
QPA backends:
  DirectFB ............................... no
  EGLFS .................................. yes
  EGLFS details:
    EGLFS i.Mx6 .......................... no
    EGLFS i.Mx6 Wayland .................. no
    EGLFS EGLDevice ...................... no
    EGLFS GBM ............................ no
    EGLFS Mali ........................... no
    EGLFS Raspberry Pi ................... yes
    EGL on X11 ........................... no
  LinuxFB ................................ yes
  VNC .................................... yes
  Mir client ............................. no
Qt Widgets:
  GTK+ ................................... no
  Styles ................................. Fusion Windows
Qt PrintSupport:
  CUPS ................................... no
Qt Sql:
  DB2 (IBM) .............................. no
  InterBase .............................. no
  MySql .................................. no
  OCI (Oracle) ........................... no
  ODBC ................................... no
  PostgreSQL ............................. no
  SQLite2 ................................ no
  SQLite ................................. yes
    Using system provided SQLite ......... no
  TDS (Sybase) ........................... no
Qt SerialBus:
  Socket CAN ............................. yes
  Socket CAN FD .......................... yes
QtXmlPatterns:
  XML schema support ..................... yes
Qt QML:
  QML interpreter ........................ yes
  QML network support .................... 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
  Path support ........................... yes
  PathView item .......................... yes
  Positioner items ....................... yes
  ShaderEffect item ...................... yes
  Sprite item ............................ yes
Qt Gamepad:
  SDL2 ................................... no
Qt 3D:
  Assimp ................................. yes
  System Assimp .......................... no
  Output Qt3D Job traces ................. no
  Output Qt3D GL traces .................. no
Qt 3D GeometryLoaders:
  Autodesk FBX ........................... no
Qt Wayland Client ........................ no
Qt Wayland Compositor .................... no
Qt Bluetooth:
  BlueZ .................................. no
  BlueZ Low Energy ....................... no
  Linux Crypto API ....................... no
Qt Sensors:
  sensorfw ............................... no
Qt Multimedia:
  ALSA ................................... no
  GStreamer 1.0 .......................... no
  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 Quick Controls 2:
  Styles ................................. Default Material Universal
Qt Quick Templates 2:
  Hover support .......................... yes
  Multi-touch support .................... yes
Qt Location:
  Gypsy GPS Daemon ....................... no
  WinRT Geolocation API .................. no
Qt WebEngine:
  Embedded build ......................... yes
  Pepper Plugins ......................... no
  Printing and PDF ....................... no
  Proprietary Codecs ..................... no
  Spellchecker ........................... yes
  WebRTC ................................. no
  Using system ninja ..................... no
  ALSA ................................... no
  PulseAudio ............................. no
  System libraries:
    ICU .................................. no
    libwebp and libwebpdemux ............. no
    Opus ................................. no
    ffmpeg ............................... no

Kind regards,
MHermann

[SGaist]

Hi,

Do you have the udev library development package installed ?

[MHermann]

@SGaist : Yes. I think I installed all important packages on my Ubuntu.

• udev
• libudev1
• libudev-dev

Ist that correct? Or is something missing?

[jsulm]

@MHermann said in How to configure Qt with enabled udev support?:

on my Ubuntu

You need them in your sysroot for your target device

[MHermann]

@jsulm: Okay. But I don't know how I get this in my sysroot. Do you know what I have to do?

[jsulm]

@MHermann Depends on how you create the sysrott. For RPi one usually puts the SD card into RPi boots it, installs what is needed, shuts it down, puts the SD into PC card reader, mounts it (read-only is better) and uses the mount directory as sysroot.

One tip: if you want to know why something is missing add -v parameter to configure call and check its output.

[MHermann]

@jsulm : And if I have the sysroot on my harddisk? Is it also possible to add udev?
Because I am using a VM and now I can not access the sd card in my Ubuntu...

[jsulm]

@MHermann said in How to configure Qt with enabled udev support?:

Is it also possible to add udev?

With quite a big effort it is. You can download the needed deb packages for your target extract them and put the content in the directories they belong to.

[MHermann]

@jsulm : Now I tried the following:

1. I installed udev on my Raspi image (udev, libudev*).
2. I copied the Raspi image from sdcard on my computer.
3. I used this image as sysroot and configured the Qt.

=> But the udev support is still disabled.

What I am doing wrong?

[SGaist]

Did you re-run configure from a clean state ?

[MHermann]

@SGaist : I re-run 'configure' again. But this time with the option '-recheck-all'. Now udev support is enabled.