Configuring framebuffer on ubuntu or debian


I have a problem running qt application in framebuffer on ubuntu and debian distroes

Using minimalist ubuntu build from

  1. Installed extra packages

sudo apt-get qt4-dev-tools
sudo apt-get install g++
sudo apt-get install make

wrote minimal qt app; run qmake, make -everything seems fine

then when running ./q -qws output message is:
cannot connect to X server

What am I am missing here?

Thank you

is the X server running? is it installed?

Qws is a standalone server itself. It does not need X or any window system.

Michail can you compile and run the same source at a PC to ensure no problems in the code? In addition you can run your application with strace to see what happens inside the application.

I’ve successfully run a qt application on a rootfs Ubuntu ARM Core, but I compiled qt from sources myself

Yes, the app runs on host fine… There is nothing in it, except a single window :slight_smile:

I did compile the app on the host fist and had the same issue; so I decided to switch to native compile to make sure that I am not making some while compiling QT libraries.

Can you share your recipe for QT cross-compile on armhf?


Did you test some other framebuffer programs to test if framebuffering is working properly?
#~ fbi test.bmp

Well… I used ALMOST the same thing…
Mine qmake.conf also has

QMAKE_CFLAGS_RELEASE = -O3 -march=armv7-a -mtune=cortex-a8 -mfpu=neon -mfloat-abi=hard
QMAKE_CXXFLAGS_RELEASE = -O3 -march=armv7-a -mtune=cortex-a8 -mfpu=neon -mfloat-abi=hard

are those unnecessary?

fbi wasn’t installed, but I did

echo aaaaaaaaaaa > /dev/fb0 and I saw color line(s) appear on the top of the display…

You should not use your own qmake flags as qmake is capable to create configuration that 100% working