I was not able to find any documentation on a VNC loadable module anywhere. Is there a place where one can find out about this? <div class="gmail_quote">On Thu, May 26, 2011 at 7:34 AM, Pat Kane <<a href="mailto:pekane52@gmail.com">pekane52@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">I like VNC and have built both loadable module and DDX version. The main problem with the DDX version is that since VNC has a GPL license I can not merge the code into my Xorg source tree. Pat --- <div><div></div><div class="h5"> On Wed, May 25, 2011 at 6:07 PM, David Jackson <<a href="mailto:djackson452@gmail.com">djackson452@gmail.com</a>> wrote: > > > On Wed, May 25, 2011 at 4:36 PM, Glynn Clements <<a href="mailto:glynn@gclements.plus.com">glynn@gclements.plus.com</a>> > wrote: >> >> David Jackson wrote: >> >> > A display driver that contains a VNC server. The problem with x11vnc is >> > that >> > it is slow, very slow. XVnc server, which is a X server that contains a >> > VNC >> > server but has no hardware drivers, is much faster since the VNC server >> > is >> > built directly into the X server, >> >> What sample size does your analysis use? How many different hardware >> configurations, and how many different applications? >> >> x11vnc has the drawback that it's reading a framebuffer which is >> typically in video memory, so the data has to be read over the bus. >> The speed of this operation may vary significantly depending upon the >> hardware being used. It may also vary depending upon the amount of >> activity (i.e. if it has to wait for the outstanding rendering >> operations to complete before it's allowed to read the framebuffer). >> >> Xvnc has the advantage that the framebuffer is in system memory. But >> this is also a drawback, as it means that all rendering is performed >> in software. Try running an application which uses OpenGL to render >> detailed scenes; you might want to reconsider your assertion about >> Xvnc is fast. >> >> IOW, it's a case of "choose your poison". x11vnc has fast rendering >> but slow export, Xvnc has slow rendering but fast export. A similar >> tradeoff exists for X11 verus VNC for remote display. >> >> > however this does not allow one to export >> > their main X display which is also displayed directly to video hardware. >> > The >> > solution here is to include a driver in the X.org main server >> > distribution >> > for a VNC server that can be loaded into the X server. The VNC server >> > driver >> > should be able to be dynamically loaded while the server is running and >> > the >> > output of the server displayed simultaneously to VNC clients and to the >> > local video hardware. This can be controlled from provided command line >> > and >> > GUI utilities. >> >> Does the VNC driver read the framebuffer on the video card (which >> suffers from the same performance issues as x11vnc), or does it >> attempt to duplicate the framebuffer by emulating whatever video >> hardware is installed? If it's the latter, the application will be >> slowed to the speed of the VNC driver's software renderer (which will >> be extremely complex, as it will have to mimic every feature which is >> available in at least one hardware driver). >> >> > One of the very severe problems I have been having is that Xvnc does not >> > support Render extensions, and many applications no longer work without >> > the >> > Render extension. VNC driver with X.org therefore must support the >> > Render >> > extension and other ones. >> >> The main "other one" being OpenGL, for which a software implementation >> will be much, much slower than a modern GPU. >> >> > Dynamic runtime enabling and disabling, configuration and setup and >> > removal >> > of display output and input drivers while the server runs without server >> > restart. this allows for instance, the user to have the X server display >> > to >> > a new target while the server runs, or display to many different display >> > outputs at the same time This includes the VNC Server driver above, this >> > allows a person to easily swtich the VNC on and off from displaying to >> > certain outputs, such as they could turn off display to the local >> > monitor >> > and then turn it back on again, or turn on and off VNC display. >> > >> > Another feature that increases flexibility to the user would be to allow >> > the >> > user to direct display of a certain window or the entire root window and >> > display over an X client connection to another server, or any number of >> > other servers. This would also forward the windows children who would >> > also >> > be displayed on the remote server inside the parent window. >> >> To do this at the protocol level requires a completely new protocol >> and significant support from the toolkit. The X protocol exposes a >> significant amount of implementation detail to the client. Much of >> that information is required to remain constant for the lifetime of >> the client. >> >> E.g. if the client queries the list of OpenGL extensions, and starts >> using some of them, there's no mechanism by which to inform the client >> that an extension is suddenly unavailable, which would be required if >> you were to "redirect" the window to a different server with different >> hardware. >> >> Even if such a mechanism existed, it's debatable how many applications >> would support it. Reconstructing the current server-side state from >> scratch is a lot of work, and toolkits can't always help (e.g. they >> won't help reconstruct the server-side OpenGL state, as the toolkit >> doesn't get involved in the rendering process). >> >> > Many users, including myself, want to have many X servers running at the >> > same time and then at run time be able to change to where these servers >> > are >> > being displayed, and as well when an app is started, to which server it >> > is >> > displayed with the -display option. >> >> AFAICT, there are only two feasible approaches to window "mobility": >> >> 1. VNC-like framebuffer sharing. The application connects to a >> specific X server which performs all rendering. You have the option to >> forward rendered images to other systems for physical display. >> >> 2. Use GUI toolkits which offer an abstract, high-level interface to >> the client. The toolkit has the ability reconstruct and clone windows >> at will. >> >> -- >> Glynn Clements <<a href="mailto:glynn@gclements.plus.com">glynn@gclements.plus.com</a>> >> _______________________________________________ >> <a href="mailto:xorg@lists.freedesktop.org">xorg@lists.freedesktop.org</a>: X.Org support >> Archives: <a href="http://lists.freedesktop.org/archives/xorg" target="_blank">http://lists.freedesktop.org/archives/xorg</a> >> Info: <a href="http://lists.freedesktop.org/mailman/listinfo/xorg" target="_blank">http://lists.freedesktop.org/mailman/listinfo/xorg</a> >> Your subscription address: <a href="mailto:djackson452@gmail.com">djackson452@gmail.com</a> > > > x11vnc is noticeably slower. I think the really annoying thing that makes it > hard to use is that there is a longer delay when typing for characters to > display on the screen than there is with Xvnc. I can notice this. When you > are typing characters do display much more quickly to the screen on Xvnc. > That is a big issue, because, it is really hard to type when you have a long > delay of characters appearing when you type them.Perhaps this is due the > polling of the framebuffer. > > The VNC driver could do its own rendering, get the graphics commands from > the application directly. Yes, you are correct that is slow for many complex > operations. You are correct, the other alternative is to grab the > framebuffer. You are correct it might be faster for those complex graphics. > Grabbing the framebuffer inside the X server and feeding it out to VNC > clients via a VNC server in the X server, might save a little bit of time by > avoiding having to be sent over a socket to another process, but i do not > know if that is true. It may be it might do all that being interrupted fewer > or no times, where with x11vnc you are gauranteed a task switch and some > time for x11vnc to get the CPU. I guess x11vnc asks for the framebuffer over > an X connection, then wait for the X server to get the CPU to process the > request, then wait again for x11vnc to get CPU and the data to be sent to > VNC clients. if we have a framebuffer based VNC driver inside the X server, > it may allow for tighter synchronisation and less delay. I cannot say how > significant it would be. > > The other issue mentioned, about the window forward feature. You are > correct. I have been thinking about these issues. It would be best for it to > be invisible to clients. Ive been thinking about these problems. > > I am know C, however I know little about X internals or X protocol. Is there > a good source of documentation that would give a person a full introduction > and overview of how the X server works,including how it all fits together, > and a tour of the system and documentation of the internals such as > functions, variables etc? Basically everything need for a person who only > knows C to learn all about how the X server works? > > > > _______________________________________________ > <a href="mailto:xorg@lists.freedesktop.org">xorg@lists.freedesktop.org</a>: X.Org support > Archives: <a href="http://lists.freedesktop.org/archives/xorg" target="_blank">http://lists.freedesktop.org/archives/xorg</a> > Info: <a href="http://lists.freedesktop.org/mailman/listinfo/xorg" target="_blank">http://lists.freedesktop.org/mailman/listinfo/xorg</a> </div></div>> Your subscription address: <a href="mailto:pekane52@gmail.com">pekane52@gmail.com</a> > </blockquote></div>