Writing to Android Frame Buffer

[Vasant]

Hi,

I am trying to write to the android frame buffer as root and nothing shows up on screen.
cat /dev/urandom > /dev/graphics/fb0
Any ideas why this doesn't work ?

Vasant

[ayufan]

Because this is not how it works. All FB processing is done by SurfaceFlinger which is responsible for managing and flushing them to screen.

[Vasant]

I is true that Androis uses Surface Flinger. But what I am trying to do is write directly though the device interface.
This does work on ODROID-C2 Android and few other devices. Perhaps it has been disabled for Allwinner.

Vasant

[MarkHaysHarris777]

hi, the frame buffer console does not work ( on the pine board ) for gnu+linux either, unless you use the experimental DRM kernel patch. 

This is a serious glitch for gnu+linux also, because power linux users leverage the six(6) frame-buffer consoles ( some call black screens ) profusely;  so for some people its a show stopper,  haha  I've actually gotten used to edit with VI without a cursor on the linux frame-buffer.

This sound even more ominous, because you can't get ANY output to the FB con ?