Talk:RaspberryPi2EGLFS

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Asking Questions

Please post questions about building Qt for Raspberry Pi in the Qt forums. This talk page can be used to talk about improving the article.

small fix to the relativelink fixing script

The script relinks also systemd files pointing to /dev/null. Although this does not break anything currently, here is a fix Copy the following and paste to shell in the directory where the sysroot-relativelinks.py is

patch <<'EOF'
*** sysroot-relativelinks.py~	Fri Apr 28 09:50:57 2017
--- sysroot-relativelinks.py	Fri Apr 28 10:56:27 2017
***************
*** 18,23 ****
--- 18,25 ----
          return
      if link.startswith(topdir):
          return
+     if link.startswith("/dev/"):
+         return
      #print("Replacing %s with %s for %s" % (link, topdir+link, filep))
      print("Replacing %s with %s for %s" % (link, os.path.relpath(topdir+link, subdir), filep))
      os.unlink(filep)
EOF

Ansible Roles/Playbooks Based on this Article

I used the instructions here to make Ansible playbooks that perform most of the same steps. The playbooks can set up a Pi, set up a development computer, and then deploy Qt to the Pi. Repo is https://bitbucket.org/johnwoltman/build_qt_for_pi_with_ansible

Minor improvement to step 8

You can combine all 5 commands into one like this:

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

Note that -R preserves the path names and that rsync creates the ./sysroot directory for us.

Hi I have Ubuntu 16.04 x64 and Qt Creator 5.10.1 x64 witch version of qt base should I choose? for compile on raspberry pi 3 with Raspbian stretch x32 OS?

Recommended changes to Step #15

Just including the line:

  ./qopenglwidget

So that way beginners (like me) know what to do to get it running.

Suggestion of changes to step 14

Make sure you're in "/home/pi" aka "~" when you run these commands:

(This would have saved me an hour...)


Cross compilation on 64bit machines TIP

Hi. When You try to build QT on 64 bit PC without i386 libraries, use:

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


Recommended changes to Step #4

Honestly, `sudo rpi-update` should only be used by Raspbian developers to the firmware or operating system itself; it pulls from the `next` branch which is usually unstable. At times, it will brick your Raspi.

Please change this to read `sudo apt-get update && sudo apt-get -y upgrade`. This will upgrade the operating system and yes, the firmware as well. It will pull from the stable `master` branch as expected.

error: undefined reference to `__cxa_throw_bad_array_new_length@CXXABI_1.3.8'

When try to build QT Creator app got an error: raspi/sysroot/usr/lib/arm-linux-gnueabihf/libicui18n.so.57:-1: error: undefined reference to `__cxa_throw_bad_array_new_length@CXXABI_1.3.8'

after some exploration add following line to .pro file: QMAKE_LFLAGS += -fuse-ld=gold

Now its ok.

Add section about changed library names

See this (part 6). I cite: "In new Raspbian stretch versions, EGL libraries have different names than those assumed in Qt configuration files, so edit the ./qtbase/mkspecs/devices/linux-rasp-pi*-g++/qmake.conf file and substitute all references to -lEGL and -LGLESv2 for -lbrcmEGL and -lbrcmGLESv2, respectively." (linux-rasp-pi*-g++ refers to the board you're using).