ui/vnc: set TCP_NODELAY

we currently have the Nagle algorithm enabled for all outgoing VNC updates.
This may delay sensitive updates as mouse movements or typing in the console.
As we currently prepare all data in a buffer and then send as much as we can
this should not cause big trouble. Well established VNC servers like TightVNC
set TCP_NODELAY as well.
A regular framebuffer update request generates exactly one framebuffer update
which should be pushed out as fast as possible.

Signed-off-by: Peter Lieven <pl@kamp.de>
fix full frame updates for VNC clients

If the client asks for !incremental frame updates, it has lost its content
so dirty doesn't matter - it has to see the full frame, so setting force_update

Signed-off-by: Stephan Kulow <coolo@suse.de>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>
vnc update fix

We need to remember has_updates for each vnc client.  Otherwise it might
happen that vnc_update_client(has_dirty=1) takes the first exit due to
output buffers not being flushed yet and subsequent calls with
has_dirty=0 take the second exit, wrongly assuming there is nothing to
do because the work defered in the first call is ignored.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Peter Lieven <pl@kamp.de>