Linux framebuffer device exportable via some VNC server?
cbeerse "at" hiscom.nl
Thu Jul 18 13:24:01 2002
> -----Original Message-----
> From: Susanne Oberhauser [mailto:froh "at" suse.de]
> Till Adam <till "at" adam-lilienthal.de> writes:
> > # Quoting Susanne Oberhauser (froh "at" suse.de):
> > > is there a vnc server which exports the Linux framebuffer device
> > > via vnc?
> > I don't think there is such a server, but I am planing to do one to
> > complement DirectVNC. ETA unknown, though ;).
> What is missing for such a beast?
> As far as I understand, the vnc servers somehow intercept change
> events on the display. How would that be accomplished with the fb
> device, being mmapped memory?
That's the hard part of the fb-vnc-server. It has to find the changes on it
self. This is done similar as on the M$Windows machine: polling relevant
areas. I'm guessing on this one, I don't know details. If it is realy
framebuffer only, not expecting to run X11, it should be capable of serving
the framebuffered text console as found on HP and Sun workstations (and some
For the default Xvnc server, it's easy: it IS the Xserver and hence it does
For the XFree server (http://xf4vnc.sourceforge.net/), it has the proper
hooks in the Xserver to receive the changes.
> I don't understand much of such things yet, but I think, once this
> change event interception is mastered, it should not be too hard to
> extend one of the existing vnc servers in such a way that it exports
> the /dev/fbX instead of some 'own' memory, shouldn't it?
I think the best example for this is the XFree server: it has the hooks in
the Xserver. Maybe, someday, someone makes the hooks in the linux kernel,
around the console messages or such. Would be nice...