[X2Go-Dev] improve Xinerama

Michael DePaulo mikedep333 at gmail.com
Tue Apr 28 13:59:18 CEST 2015


Hi Ulrich (see bottom reply),

On Tue, Apr 28, 2015 at 6:46 AM, Ulrich Sibiller <uli42 at gmx.de> wrote:
> Hello,
>
> I have been playing around with x2go and xinerama. While the current
> setup kind of works there are some problems with the current concept:
> - it uses LD_LIBRARY_PATH. Any software that fiddles around with
> LD_LIBRARY_PATH can break it (and there a lot (mostly commercial)
> programs doing that...)
> - it does not fully work on mixed architecture setups (32/64bit mix)
> because there's only one library in the distribution. (I haven't
> tested this but it AFAIK you cannot link a 32bit library to a 64
> binary an vice versa.)
> - requesting xinerama information (xdpyinfo -ext XINERAMA) does only
> work for programs that are started inside the session. You cannot
> request Xinerama information by redirecting $DISPLAY for the calling
> program. You'd as well have to set the LD_LIBRARY_PATH variable.
> - connection to an other host using ssh -X other-host leads to a
> working shell that has a DISPLAY. However, it is not able to request
> the correct Xinerama information.
> - probably more
>
> The reason for all this is the chosen approach. Patching the
> libXinerama.so only works for clients actually able to access the
> patched library. If - for whatever reason - they are using the
> standard libXinerama this fails. So I really think the patched library
> should vanish completely. Instead
> nx-X11/programs/xserver/Xext/panoramix.c should be extended to do a
> lookup to the nx client side whenever an X client is asking the
> nxagent/x2goagent for Xinerama information.
>
> What do you think? Is there anything I am missing here?

1. We don't patch Xinerama. Rather, nx-libs, our "X server", includes
an outdated version:
nx-X11/lib/Xinerama

2. We are indeed working on dropping as many of nx-libs's bundled
libraries as possible. We replace them with the system's versions.
Often this means modifying files under nx-X11/programs/xserver/ like
the one you mentioned. I am not sure what the schedule is for
libXinerama, but I assume it is on the list. All this work is being
done on the nx-libs 3.6.x branch.
http://code.x2go.org/gitweb?p=nx-libs.git;a=shortlog;h=refs/heads/3.6.x
https://github.com/ArcticaProject/nx-libs/tree/3.6.x

3. Hopefully someone can comment on the timetable for dropping the
bundled libXinerama. Still, just because we dropped libXinerama
doesn't mean we will immediately release nx-libs 3.6.0; We will
probably drop other libraries 1st.

-Mike#2


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