Crashing the window mgr from GL programs

[Jean-Francis Balaguer]

In article <1990Aug3.075057.11705 at cs.umn.edu>, slevy at poincare.geom.umn.edu (Stuart Levy) writes:
> We use a locally-written 3-d object viewer on our Irises (personal and GTX).
> For some aberrant objects, or possibly some xform matrices pushed on the stack,
> we find it causes the window server to crash -- with messages resembling
> "timeout: graphics FIFO still > 1/2 full" and/or "window server killed with
> signal 15".  In extreme cases it can cause our GTX Iris to lock up such that
> we must reboot to recover the graphic display, though normally we're just
> kicked back to a login: prompt.
> 
> Does anyone know what kinds of geometric data can wedge the graphics subsystem
> this way?  If we knew what to avoid we might be able to change our application
> to prevent crashes.
> 
> 	Stuart Levy, Geometry Group, University of Minnesota
> 	slevy at geom.umn.edu


We had the same problem here not specially on personal iris but on every kind
of SGI machines.
It was coming from an accumulation of wrong gl calls. The most dangerous one
was n3f called with NaN coordinates.

We think SGI should provide a debug version of GL where every inconsistent
call to the library should be trapped as it took us more than 3 days to find the 
problem.

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Francis Balaguer
Departement d'Informatique                      Tel : 41-21-6935244
Laboratoire d'Infographie                       FAX : 41-21-6933909
Ecole Polytechnique Federale de Lausanne
CH-1015 LAUSANNE

E-Mail : balaguer at ligsg2.epfl.CH
         balaguer at elma.epfl.CH
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