consider interaction between i915 perf an cmd parser #9
Description
There's a slightly awkward backwards compatibility issue involving Mesa...
Mesa currently has some code to try and allow configuring the OA unit which involves always testing whether it's possible to write to oacontrol via an LOAD_REGISTER_IMM command which can interfere with the i915 perf driver managing oacontrol.
Trying to remove oacontrol from the whitelist in the cmd parser can result in some older versions of Mesa crashing. (todo: dig up which versions this affected)
If we land my GL_INTEL_performance_query driver then my series removes the can_write_oacontrol() test in intel_extensions.c