BeagleBoard/video

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Revision as of 19:26, 13 May 2012 by Mysli (Talk | contribs) (Power saving hint)

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This article describes information regarding video output on the BeagleBoard.

omapfb

The current framebuffer diver has a generic interface (/dev/fb) but also a specific OMAP (2 and 3) interface for YUV overlays (/dev/fb1).

In order to use the YUV overlays (/dev/fb1) you need to specify some kernel parameters:

video=omapfb:vram:2M,vram:4M

For this particular case you'll need a corresponding consistent DMA size configuration:

CONFIG_FB_OMAP_CONSISTENT_DMA_SIZE=6

In order for the display controller to work you'll need a patch from Mans Rullgard which can be found here. (At least at the time of this writing it's still needed 2.6.27-omap1)

For examples of how to use the custom omapfb see:

DVI

In order to disable/enable the video chip, insert a 0(off) or 1(on) into /sys/devices/platform/omapdss/display<X>/enabled:

echo 0 > /sys/devices/platform/omapdss/display0/enabled
echo 0 > /sys/devices/platform/omapdss/display1/enabled

Thanks this hint it will save 0.7Watts of Power if none Video is needed (i.e. runlevel 3).