Bug in interaction between freeglut and mesa-7.3-rc2
floe at butterbrot.org
Sat Jan 17 02:28:38 PST 2009
>> The bug causes a segfault in libGL.so, though even with debug info
>> enabled, I can't see the exact location. However, I can work around the
>> bug when, in freeglut, I replace
> Why would you do that? There is no improvement to freeglut and no
> benefit to its users. If the read drawable and the drawing drawable are
> always the same, just use glXMakeCurrent. You already have a tool that
> does *exactly* the job you need done. Why change to a tool that is
> intended to suit a different need?
Uh, I do that because I need to use freeglut with the opensource drivers
and DRI? It won't work otherwise. Note: freeglut currently contains
_glxMakeContextCurrent_, which I replaced by _glXMakeCurrent_, not the
other way round.
If I remember correctly, I already posted this patch to the freeglut
mailing list last fall, where it was rejected, citing possible side
effects on other platforms. As I am not a regular freeglut developer, I
accepted that and (wrongly) concluded that it has to be fixed in Mesa.
So let me summarize:
- there is a bug in Mesa which causes glxMakeContextCurrent to segfault,
- but it only occurs because freeglut doesn't call glXMakeCurrent, as it
really should, and passes invalid parameters, too.
If that is correct, could somebody with more authority than me
please convince the freeglut guys to fix it? As freeglut is the default GLUT
implementation on most distros, I consider this quite important for
acceptance of the opensource DRI drivers.. a _lot_ of software uses GLUT,
and consequently crashes.
"_Nothing_ brightens up my morning. Coffee simply provides a shade of
grey just above the pitch-black of the infinite depths of the _abyss_."
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