Virtual Framebuffer on UM

[Andrew Clunis <orospakr@orospakr.is-a-geek.org>]

Hey, all!

I've been hacking on the UM kernel to reenable framebuffer support, in
preparation for writing a driver using SDL (http://libsdl.org).  The
only things I have modified (at least with this tree, heh heh) so far
were to add 'source drivers/video/Kconfig' to arch/um's Kconfig, and
patch fbmem.c to disable caching on the UM arch.  This is in the fb_mmap
function, in all those messy #ifdefs around the arch specific calls to
disable caching on the video memory.

I have a 2.6.6 UM kernel with the aforementioned patches that has been
booted with video=vfb:, and displays:
  fb0: Virtual frame buffer device, using 1024K of video memory
in the kernel messages.

I've ensured /dev/fb0 device node has major 29 and minor 0.

However, when I do 'cp /dev/fb0 /root/blob', I get a file of size 0.  I
was expecting a 1 meg file.

Is this normal behavior?  

p.s. Geert, where can the source for your old GDK UM driver be found,
the one that had the -lpthread trouble?  I have a design that will
(hopefully) not have those issues, but I'm curious as to how you tackled
the rest of it.  (SDL itself has a -lpthread dependency, but I can get
around this. The graphical component of SDL does not require pthreads,
so as long as I don't init the audio or threading components, I should
be OK)

-- 
Regards,
Andrew Clunis

http://orospakr.is-a-geek.org/



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