Under Enterprise Linux 5, when attempting to render to an offscreen area, any program crashes when attempting to begin the opengl rendering (gdk_gl_drawable_gl_begin function on an offscreen area) with DRI enabled. This can be reproduced with both the open source Intel driver (i810), as well as the latest proprietary driver from Intel (IEGD6.1) on a Mobile Intel 915GM Express Graphics Memory Controller. It works fine on an ATI Radon RV100 with the open source driver under Fedora 5.
The example program pixmap included with the GtkGlExt (1.2.0) library produces this crash every time on the intel card:
[user@ge8 ~]$ DISPLAY=:0.0 ./pixmap

OpenGL extension version - 1.3

OpenGL visual configurations :

gdk_gl_config_is_rgba (glconfig) = TRUE
gdk_gl_config_is_double_buffered (glconfig) = FALSE
gdk_gl_config_is_stereo (glconfig) = FALSE
gdk_gl_config_has_alpha (glconfig) = TRUE
gdk_gl_config_has_depth_buffer (glconfig) = TRUE
gdk_gl_config_has_stencil_buffer (glconfig) = TRUE
gdk_gl_config_has_accum_buffer (glconfig) = TRUE

GDK_GL_USE_GL = TRUE
GDK_GL_BUFFER_SIZE = 32
GDK_GL_LEVEL = 0
GDK_GL_RGBA = TRUE
GDK_GL_DOUBLEBUFFER = FALSE
GDK_GL_STEREO = FALSE
GDK_GL_AUX_BUFFERS = 0
GDK_GL_RED_SIZE = 8
GDK_GL_GREEN_SIZE = 8
GDK_GL_BLUE_SIZE = 8
GDK_GL_ALPHA_SIZE = 8
GDK_GL_DEPTH_SIZE = 24
GDK_GL_STENCIL_SIZE = 8
GDK_GL_ACCUM_RED_SIZE = 16
GDK_GL_ACCUM_GREEN_SIZE = 16
GDK_GL_ACCUM_BLUE_SIZE = 16
GDK_GL_ACCUM_ALPHA_SIZE = 16

The OpenGL rendering context is created
The program 'pixmap' received an X Window System error.
This probably reflects a bug in the program.
The error was 'BadWindow (invalid Window parameter)'.
  (Details: serial 167 error_code 3 request_code 3 minor_code 0)
  (Note to programmers: normally, X errors are reported asynchronously;
   that is, you will receive the error a while after causing it.
   To debug your program, run it with the --sync command line
   option to change this behavior. You can then get a meaningful
   backtrace from your debugger if you break on the gdk_x_error() function.)