Can I bypass framebuffer with Qt?

davem

Take a look at the gfxdriver plugins sources. For example, I recall the eglnullws plugin derives a QScreen class for a fullscreen EGL context without referencing the linux framebuffer.

jwilkie

Hey guys, back at it again after a hiatus.
So I've built my custom screen class and plugin and made a .so library as a result. My question now is how to go about installing it. I've tried putting this library in:
targetfs/usr/lib/qt/plugins folder and then running my application with the switch -display -<name> with name being in the keys() routine in the plugin. But it fails with: driver not found. So I'm probably missing some installation instructions. It is a totally custom driver so I'm not using any of the Qt built in ones. Do I need to run a configure script entry such as "./configure -qt-gfx-<name>" ?
It seems I don't because those commands enable some of the built in drivers.

Any hints on this I'd appreciate it, thanks!

SGaist

Did you also create a "QScreenDriverPlugin":http://qt-project.org/doc/qt-4.8/qscreendriverplugin.html ?

jwilkie

Yes I did create a class that inherits QScreenDriverPlugin. And it references my custom QScreen. So I built those into a .so file and I installed it in usr/lib/qt/plugins. But still, the driver doesn't seem to be recognized.

jwilkie

Another possible hint.. After my failed attempt at running my application, I noticed that a file got created "Trolltech.conf" and in it some info about my custom driver "libpebble.so" that it doesn't seem to like?

cat Trolltech.conf

[Qt Plugin Cache 4.7.false]
usr\lib\qt\plugins\gfxdrivers\libpebble.so=40704, 0, arm linux g++-4 full-config, 2013-04-18T19:55:30

SGaist

I thought there was something more ! Have a look at "this":http://qt-project.org/doc/qt-4.8/deployment-plugins.html#loading-and-verifying-plugins-dynamically there are some advice to deploy the plugins and troubleshoot them.

jwilkie

Thanks SGaist, this Deploying Plugins page has some helpful trouble shooting tips. I need to make sure I am building my application and Qt libraries in the same mode and version. Going to revisit my build process.

SGaist

You're welcome !

And don't forget to clear the cache (always worth a try)

jwilkie

Ok, how do I clear the cache?

SGaist

IIRC, theres is a config file created in the home directory .config/ something that you can simply remove.

jwilkie

ok. on my target it was /root/Settings/Trolltech.conf (I'm using Qt 4.7.4).

So I got Qt to recognize my driver, what helped me was the env variable QT_DEBUG_PLUGINS. With that set it would show me the errors when it was loading my plugin, and that pointed me to the problems.