[Mesa-dev] [PATCH] i965: Fix border color on Sandybridge and Ivybridge.

[Kenneth Graunke]

While reading through the simulator, I found some interesting code that
looks like it checks the sampler default color pointer against the bound
set in STATE_BASE_ADDRESS.  On failure, it appears to program it to the
base address itself.

So I decided to try programming a legitimate bound, and lo and behold,
border color worked.  Unfortunately, it's not entirely reliable: piglit
tests (such as tex-border-1) will still fail if you run them in a loop.

+92 piglits on Sandybridge.  Also fixes Lightsmark on Ivybridge.

NOTE: This is a candidate for stable release branches.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=28924
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=38868
Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
 src/mesa/drivers/dri/i965/brw_misc_state.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

v2: OUT_RELOC is your friend.  Thanks to ickle for pointing out my silly
    mistake.  Now regression free and fixing lots of tests.  And demos!

diff --git a/src/mesa/drivers/dri/i965/brw_misc_state.c b/src/mesa/drivers/dri/i965/brw_misc_state.c
index 8e59a47..1a7d328 100644
--- a/src/mesa/drivers/dri/i965/brw_misc_state.c
+++ b/src/mesa/drivers/dri/i965/brw_misc_state.c
@@ -769,7 +769,13 @@ static void upload_state_base_address( struct brw_context *brw )
 		 1); /* Instruction base address: shader kernels (incl. SIP) */
 
        OUT_BATCH(1); /* General state upper bound */
-       OUT_BATCH(1); /* Dynamic state upper bound */
+       /* Dynamic state upper bound.  Although the documentation says that
+	* programming it to zero will cause it to be ignored, that is a lie.
+	* If this isn't programmed to a real bound, the sampler border color
+	* pointer is rejected, causing border color to mysteriously fail.
+	*/
+       OUT_RELOC(intel->batch.bo, I915_GEM_DOMAIN_INSTRUCTION, 0,
+		 intel->batch.bo->size | 1);
        OUT_BATCH(1); /* Indirect object upper bound */
        OUT_BATCH(1); /* Instruction access upper bound */
        ADVANCE_BATCH();
-- 
1.7.7.5