i965: Use the correct restart index for fixed index mode on Haswell.
authorKenneth Graunke <kenneth@whitecape.org>
Fri, 24 May 2013 16:28:56 +0000 (09:28 -0700)
committerKenneth Graunke <kenneth@whitecape.org>
Wed, 29 May 2013 21:22:06 +0000 (14:22 -0700)
commit7c87a3b5dac118697a9b67caa7b6d5cab60f316d
treeb27670459cc44a122bfb3c4dce42c6754bea76fb
parent1569709663f5ad3c339494f756bcc05f37044182
i965: Use the correct restart index for fixed index mode on Haswell.

The code that updates the ctx->Array._RestartIndex derived state mashed
it to 0xFFFFFFFF when GL_PRIMITIVE_RESTART_FIXED_INDEX was enabled
regardless of the index buffer type.  It's supposed to be 0xFF for byte,
0xFFFF for short, or 0xFFFFFFFF for integer types.

The new _mesa_primitive_restart_index() helper gets this right.

The hardware appears to compare against the full 32-bit value some of
the time, causing primitive restart not to occur when it should.  The
fact that it works some of the time is rather frightening.

Fixes sporadic failures in the ES 3 instanced_arrays_primitive_restart
conformance test when run in combination with other tests.

NOTE: This is a candidate for the 9.1 branch.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
src/mesa/drivers/dri/i965/brw_primitive_restart.c