[Interest] Qt 5.2 scenegraph does not draw anything for our MIPS cpu/VIVANTE GPU platform

Narayanarao Rao nari01 at gmail.com
Wed Nov 6 00:05:34 CET 2013

I am able to build qtbase and qtdeclarative from git with a few changes for
our MIPS "74kf -mdspr2" platform. I use eglfs plugin.

If I don't pass any qml file to qmlscene, eglfs does gltexsubimage2d of a
qimage (file selection dialog). That works fine. I can see the file
selection dialog, though with very small text.

eglfs with Qt 5.0 works fine - I can see output on screen for all qmls.

We use Qt 4.8 simplegl for our production releases and that works fine too.

However, with Qt 5.2 new scenegraph changes, if I pass a qml file to
qmlscene, I just see the screen cleared to white and nothing gets drawn
after that. When I enable render_timing etc. environment veriables, I see
everything printed normally - I see that it takes some time for render,
sync, animations etc. It also takes expected CPU when doing QML animations.
I tried both qmls with an image as well as rect. I suspect our GPU does not
like the new shader code. I ported apitrace to our platform and compared
traces for case where I see output on screen (qmlscene without qml file
input) and where I don't see output on screen (qmlscene with any qml file).
Both look similar except for differences in vertex and fragment shaders.

Anything I should try?
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