Mesa (master): i965/gen6: Fix GPU hang when using stencil buffer without depth

[Chad Versace]

Module: Mesa
Branch: master
Commit: f99d5af03b0f97d7a1b7076b2142069770879471
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=f99d5af03b0f97d7a1b7076b2142069770879471

Author: Chad Versace <chad.versace at linux.intel.com>
Date:   Wed Nov 23 10:06:46 2011 -0800

i965/gen6: Fix GPU hang when using stencil buffer without depth

Enable the bit 3DSTATE_DEPTH_BUFFER.Tiled_Surface.  From the Sandybridge
PRM, Volume 2, Part 1, Section 7.5.5.1.1 3DSTATE_DEPTH_BUFFER, Bit 1.27
Tiled Surface:
   [DevGT+]: This field must be set to TRUE.

Fixes GPU hangs on the following Piglit tests:
   hiz-stencil-test-fbo-d0-s8
   hiz-stencil-read-fbo-d0-s8

Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
Signed-off-by: Chad Versace <chad.versace at linux.intel.com>

---

 src/mesa/drivers/dri/i965/brw_misc_state.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_misc_state.c b/src/mesa/drivers/dri/i965/brw_misc_state.c
index 17da460..cb1405c 100644
--- a/src/mesa/drivers/dri/i965/brw_misc_state.c
+++ b/src/mesa/drivers/dri/i965/brw_misc_state.c
@@ -278,6 +278,10 @@ static void emit_depthbuffer(struct brw_context *brw)
        *
        *     [DevGT]: This field must be set to the same value (enabled or
        *     disabled) as Hierarchical Depth Buffer Enable
+       *
+       * The tiled bit must be set. From the Sandybridge PRM, Volume 2, Part 1,
+       * Section 7.5.5.1.1 3DSTATE_DEPTH_BUFFER, Bit 1.27 Tiled Surface:
+       *     [DevGT+]: This field must be set to TRUE.
        */
       struct intel_region *region = stencil_irb->mt->region;
 
@@ -290,6 +294,7 @@ static void emit_depthbuffer(struct brw_context *brw)
 	        (1 << 21) | /* separate stencil enable */
 	        (1 << 22) | /* hiz enable */
 	        (BRW_TILEWALK_YMAJOR << 26) |
+	        (1 << 27) | /* tiled surface */
 	        (BRW_SURFACE_2D << 29));
       OUT_BATCH(0);
       OUT_BATCH(((region->width - 1) << 6) |