When I use glEnable(GL_PRIMITIVE_RESTART_FIXED_INDEX) it uses the value set by glPrimitiveRestartIndex() and not the max value of the index data type: 
GL_UNSIGNED_BYTE -> 0xFF
GL_UNSIGNED_SHORT -> 0xFFFF
GL_UNSIGNED_INT -> 0xFFFFFFFF

Basicaly it just behaves like glEnable(GL_PRIMITIVE_RESTART)


glxinfo|grep OpenGL

OpenGL vendor string: X.Org
OpenGL renderer string: Gallium 0.4 on AMD PITCAIRN
OpenGL core profile version string: 3.3 (Core Profile) Mesa 10.4.0-devel (git-5814185 2014-10-08 trusty-oibaf-ppa)
OpenGL core profile shading language version string: 3.30
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile
OpenGL core profile extensions:
OpenGL version string: 3.0 Mesa 10.4.0-devel (git-5814185 2014-10-08 trusty-oibaf-ppa)
OpenGL shading language version string: 1.30
OpenGL context flags: (none)
OpenGL extensions:
OpenGL ES profile version string: OpenGL ES 3.0 Mesa 10.4.0-devel (git-5814185 2014-10-08 trusty-oibaf-ppa)
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.0
OpenGL ES profile extensions:

uname -a

Linux c01 3.13.0-37-generic #64-Ubuntu SMP Mon Sep 22 21:28:38 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux