[Libdlo] DirectFB support?

[Bernie Thompson]

Hi Tim,

On Thu, Dec 16, 2010 at 6:39 PM, Tim Stowell <stowellt at gmail.com> wrote:
> I have successfully compiled Directfb, and whenever I try to run an
> example program, it says everything is working but all I see is a
> green screen.

Because DirectFB doesn't send down the custom damage notification
ioctl that udlfb needs to know what parts of the framebuffer are being
touched, nothing would get pushed over USB (even if everything is
working), so the screen would stay as it was originally painted at
initialization (green).

What you'll want to do is turn on udlfb's optional "defio" feature.
This enables using page faults for detecting framebuffer accesses, so
that udlfb can work with any framebuffer client (like DirectFB or the
stock xf86-video-fbdev driver) without any patches.

This defio feature is working much better now with the fixes in recent
versions of udlfb (from git.plugable.com or in kernel 2.6.37), in
combination with any kernel after 2.6.35 (for some critical defio
fixes).  It also works on older kernels, but with horizontal lines of
dead pixels that accumulate.

Documentation of the defio option is in the kernel tree:
http://www.linuxhq.com/kernel/v2.6/37-rc1/drivers/staging/udlfb/udlfb.txt

Please let us know how things go.

Best wishes,
Bernie