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

[Sletta Gunnar]

I find it very strange that qmlscene without an input file would produce the same apitrace as a qmlscene with a file. The apitrace is a reflection what we try to draw after all and that is highly dependent on what the input is. What does the trace look like?

It is a long-shot, but you could try https://codereview.qt-project.org/#change,69666

cheers,
Gunnar

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Fra: interest-bounces+gunnar.sletta=digia.com at qt-project.org [interest-bounces+gunnar.sletta=digia.com at qt-project.org] på vegne av Narayanarao Rao [nari01 at gmail.com]
Sendt: 6. november 2013 00:05
To: Interest at qt-project.org
Emne: [Interest] Qt 5.2 scenegraph does not draw anything for our MIPS cpu/VIVANTE GPU platform

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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