[PC-BSD Testing] Screen sharing

Kris Moore kris at pcbsd.com
Fri Feb 20 07:38:03 PST 2009

Walt Pawley wrote:
> At 12:29 AM -0800 2/15/09, Walt Pawley wrote:
>> Now that everyone is busy testing 7.1, I have an issue with -
>> uname -a
>> FreeBSD compaq 7.1-PRERELEASE FreeBSD 7.1-PRERELEASE #0: Mon
>> Nov 24 20:22:16 EST 2008
>> root at pcbsdx32-7:/usr/obj/pcbsd-build/cvs/7.0.2-src/sys/PCBSD
>> i386
>> - that I can't seem to find any discussion on.
>> The tale: I ran a 1.5.1 system that was working well. If it had
>> screen sharing, I was too dumb to find it so I used the x11vnc
>> port instead. No problems that I could see. I put off upgrading
>> until 7.0.2 seemed to settle down. I didn't look for screen
>> sharing. I just installed x11vnc and started trying to use it.
>> This did not work well. It seemed to behave as though the
>> sleep/screen saver would kick in on the VNC window after only a
>> few seconds. It could be awakened just about long enough to
>> position the mouse and hit a button ... if you knew right where
>> it was. So, I started looking for a reason. Still haven't found
>> one but I did discover Screen Sharing.
>> So, I tried it. It did not behave well either. It seemed to
>> provide two screen images, offset by about a 1/4-inch, mushed
>> together. On top of that are flickering, moving color blocks.
>> The system seems to work well used at the console. No funny
>> screen artifacts. No quick sleep or screen saver invocations.
>> I've not changed my viewer, though I experimented with a range
>> of its settings to see what the behavior would be, and am, in
>> fact, using it to type this message right now (not via a PC-BSD
>> machine, however).
>> Anyone with similar results or sage advice or ???
> Interestingly, either no one else has experienced this or it's
> considered too elementary to bother commenting upon. I did find
> out something about, none the less. I wrote Karl Runge about
> x11vnc and it's apparent change in behavior moving from PC-BSD
> 1.5.1 to PC-BSD 7.0.2. He quickly and kindly pointed me to
> <http://www.karlrunge.com/x11vnc/faq.html#faq-kde-screensaver>
> which pointed out that if I'd been just a bit smarter I could
> have solved my immediate problem all by myself. But it also
> pointed out that the problem is old and was probably something
> fixed in is PC-BSD's KDE3 that's reappeared in KDE4.


I'm testing this here now as well, using the KDE Desktop Sharing daemon, 
and vncviewer on another system. I see the same error where it looks 
like two offset images, with flickering color blocks. When I force the 
encoding to use "raw" the image ghosting goes away, but I still get 
weird color blocks on the viewer when I try to move windows around. I'll 
keep hunting and see i I can figure this out. I want to get a PBI built 
of the vnc client here soon, so users can easily remote-control their 
desktops, but it would be nice if it worked first :)


Kris Moore
PC-BSD Software

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