Xdmx issues

Nijveen, Harm harm.nijveen at wur.nl
Mon Jun 28 05:21:32 PDT 2010


I am trying to get Xdmx working on a 12 screens/3machines setup and came across some problems.

Using the "xorg-x11-server-extra" package in OpenSuse 11.3 RC1 (X11R7.5) I do get Xdmx running together with Gnome and using Xinerama. However, when a window is dragged across a screen boundary the window does not get redrawn (it turns grey), unless the screen boundary is between two screens attached to different PCs. Any ideas where to look for a solution? Is this a Xinerama problem?

The right two colums of the 4x3 setup show strange distortions, like parts of windows from previous Xdmx sessions or a black and white diagonal banding pattern. It looks like uninitialized memory is being displayed. This already happens if I run gnome with Xdmx on one machine using four screens, but not when I run gnome directly with the local X server. How can I debug this further?

Another issue involves a segfault of Xdmx when starting Glx programs, like glxgears, glxinfo etc.:

Program received signal SIGSEGV, Segmentation fault.
0x00000000005abdb2 in __glXGetVisualConfigs (cl=0x9fbbf0, pc=0x9f57c0 "\214\016\002") at glxcmds.c:1546
1546        reply.numVisuals = pGlxScreen->numGLXVisuals;
(gdb) bt
#0  0x00000000005abdb2 in __glXGetVisualConfigs (cl=0x9fbbf0, pc=0x9f57c0 "\214\016\002") at glxcmds.c:1546
#1  0x00000000005a50e7 in __glXDispatch (client=0x9f5420) at glxext.c:460
#2  0x000000000053d7e6 in Dispatch () at dispatch.c:445
#3  0x000000000052f03e in main (argc=7, argv=0x7fffffffe458, envp=0x7fffffffe498) at main.c:285
(gdb) print pGlxScreen
$1 = (__GLXscreenInfo *) 0x0

It looks like a X_GLXGetVisualConfigs request is recieved and handled, but glxInitVisuals was never called and so  "pGlxScreen = &__glXActiveScreens[screen];" returns 0.
Any ideas how to get around this? I really would like to be able run OpenGL applications using Xdmx and Chromium, but that is not possible right now.

About the configuration:
>From the Xdmx logging:
(II) dmx: Generation:         1                                                                          
(II) dmx: DMX version:        1.2.20070424 (DMX Project)                                                 
(II) dmx: DMX Build OS:       openSUSE (SUSE LINUX)                                                      
(II) dmx: DMX Build Compiler: gcc 4.5.0                                                                  
(II) dmx: DMX Execution OS:   Linux 2.6.34-9-desktop #1 SMP PREEMPT 2010-06-03 18:33:51 +0200          
Vendor release:  10800000      

Videocard: NVidia Quadro FX 4700 X2
Driver: NVIDIA-Linux-x86_64-256.35
Using TwinView

Any help is appreciated.

Harm Nijveen

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