segfault in multithread OpenGL app on i915

[Brian Paul]

Nickolay Kolchin wrote:
> Hello,
> 
> I have a weird problem with multithread application on i915 chipset
> (i810 DRI driver). Application segfaults when trying to use OpenGL
> functions from second thread.
> 
> All necessary initialization is perfomed in application, ie 
> XInitThreads, etc.
> 
> Tested on Suse 10.1 (xorg 6.8, 20050225 i810 driver) and Gentoo
> LiveDVD (xorg 7.0, 1.4.2 i810 driver).
> 
> This code works fine with NVidia drivers. (for several years)
> 
> Is this a driver bug? a Mesa bug? a well-known bug that nobody is
> going to fix in near future? Or this is my programming error?

Have you tried the Mesa/progs/xdemos/glthreads.c program?

It's pretty simple, but might be a good cross-check.

In my experience, Xlib's thread safety is pretty fragile.  Even with 
XInitThreads(), XLock/UnlockDisplay(), etc. it's hard to get threaded 
apps working reliably.

-Brian