L4Android/L4Linux Beagleboard framebuffer and driver

Adam Lackorzynski adam at os.inf.tu-dresden.de
Wed Sep 21 16:53:35 CEST 2011

On Tue Sep 20, 2011 at 13:52:47 +0200, giowck wrote:
> L4Android is booting up and running on my BeagleBoard (rev. C4),
> although in command line mode only. So it would be nice getting even the
> framebuffer to work, in order to see the Android GUI over video output.
> As it is now, the framebuffer seems loading at boot time, but I
> don't get any video output from HDMI/DVI neither from the
> touchscreen (Beagletouch from Liquidware). Please see [1] for the
> bootstrap log.

The LCD driver which is in there only hijacks what u-boot has already
setup. It doesn't do any initialization on its own.

> Maybe this is due the missing drivers in the kernel, since when
> configuring (ie. menuconfig) the l4android kernel, I see 'System
> type' pointing to 'L4Linux', but some OMAP3 related drivers are only
> visible and thus available, when 'TI_OMAP' is selected in the
> 'System type' config parameter.
> Is there a way to build Linux for L4 as target, but including OMAP3
> (video/multimedia) drivers?

Not possible. Requires considerable effort to make this possible.
> I did not found any docs on this topic.
> Is it possible to load linux drivers without having to modify the
> underlying parts (fiasco/L4Re)? I mean do I have to add something to
> my omap3.devs file, or are the linux driver able to interact
> directly with the hardware on board?

Difficult. On ARM the drivers usually have cross dependencies to other
modules of which some are handling core functionality which one does not
want to pass to a VM.

Adam                 adam at os.inf.tu-dresden.de
  Lackorzynski         http://os.inf.tu-dresden.de/~adam/

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