Status of backing store support?
astrand at cendio.se
Thu Mar 12 08:30:48 PDT 2009
Can anyone tell me about the status of the backing store support these
days? I wonder:
* Should miInitializeBackingStore() be used? I've found the comment in
"There is no longer an mi implementation of backing store. This function
is only for source compatibility with old drivers."
However, the function is not an no-op, and there are still servers that
calls this function. This includes Xvfb, Xwin, kdrive and DMX.
* Assuming that Composite can provide backing store support, why is
backing store disabled by default, even if Composite is used? If a server
such as Xvfb or Xvnc wants to enable backing store by default, does it
have to do anything else than just set "pScreen->backingStoreSupport=Always"?
* Backing store doesn't really seem to work reliable; it would be nice if
http://bugs.freedesktop.org/show_bug.cgi?id=19654 could get some
My primary objective is to make sure Xvnc in TigerVNC can properly run
KDE4. The easy solution is to simply remove
"pScreen->backingStoreSupport=Always", but I'd like to know if this is the
"correct" way of doing it. Of course, it will still crash if "+bs" is
manually specified, just like the normal Xorg, due to the bug above.
Peter Åstrand ThinLinc Chief Developer
Cendio AB http://www.cendio.com
Wallenbergs gata 4
583 30 Linköping Phone: +46-13-21 46 00
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