If you have an old Intel GMA and run glxinfo, you'll get this:
$ glxinfo name of display: :0 X Error of failed request: BadAlloc (insufficient resources for operation) Major opcode of failed request: 153 (GLX) Minor opcode of failed request: 3 (X_GLXCreateContext) Serial number of failed request: 22 Current serial number in output stream: 25
which is practically "So long, and thanks for all the fish!" message from X developers. 3D acceleration no longer works. Workaround is to issue
echo "export LIBGL_ALWAYS_SOFTWARE=1" >> .bashrc
to turn it off.
Thanks for reporting your workaround here. Did you also brought the regression to the attention of the MESA devs? Old/junk hardware is not something that could be deeply tested...
The link to freedesktop bugzilla I posted doesn't count? I gather, they know already.