Thursday, July 7, 2011

Running Qt+GLES on OMAP4

Certain versions of OMAP4 kernel may not enable Alpha channel by default. You can check this out by running fbset on the target:

root@omap4430-panda:/opt/targetfs# fbset

mode "1280x720-60"
# D: 74.250 MHz, H: 45.000 kHz, V: 60.000 Hz
geometry 1280 720 1280 720 32
timings 13468 110 220 5 20 40 5
accel false
rgba 8/16,8/8,8/0,0/0
endmode


This causes an initialization failure in Qt's PowerVR graphics driver plugin with an error:
/dev/fb0: could not find a suitable PVR2D pixel format

The current plugin code supports only RGB565, ARGB4444 and ARGB32 formats. The fix is to set the Frame Buffer format to ARGB32

root@omap4430-panda:~#./fbset -rgba 8/16,8/8,8/0,8/24
root@omap4430-panda:~# ./fbset

mode "1280x720-60"
# D: 74.250 MHz, H: 45.000 kHz, V: 60.000 Hz
geometry 1280 720 1280 720 32
timings 13468 110 220 5 20 40 5
accel false
rgba 8/16,8/8,8/0,8/24
endmode

If the default fbset command doesn't have any effect (i.e. Alpha is still not enabled), download fbset v2.1, cross compile and run on target

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