[Mesa-dev] [PATCH] i965: Never enable the GS on Gen6.

[Kenneth Graunke]

Prior to Gen6, we use the GS for breaking down quads, quad-strips,
and line loops.  On Gen6, earlier stages already take care of this,
so we never need the GS.

Since this code is likely completely untested, remove it for now.
We can write new code when enabling real geometry shaders.
---
 src/mesa/drivers/dri/i965/gen6_gs_state.c |   48 +++++++++-------------------
 1 files changed, 16 insertions(+), 32 deletions(-)

Tested on Sandybridge with a full piglit and ES2 run.  No changes.

diff --git a/src/mesa/drivers/dri/i965/gen6_gs_state.c b/src/mesa/drivers/dri/i965/gen6_gs_state.c
index 7296c7c..c1d0a73 100644
--- a/src/mesa/drivers/dri/i965/gen6_gs_state.c
+++ b/src/mesa/drivers/dri/i965/gen6_gs_state.c
@@ -44,38 +44,22 @@ upload_gs_state(struct brw_context *brw)
    OUT_BATCH(0);
    ADVANCE_BATCH();
 
-   if (brw->gs.prog_bo) {
-      BEGIN_BATCH(7);
-      OUT_BATCH(_3DSTATE_GS << 16 | (7 - 2));
-      OUT_RELOC(brw->gs.prog_bo, I915_GEM_DOMAIN_INSTRUCTION, 0, 0);
-      OUT_BATCH(GEN6_GS_SPF_MODE |
-		(0 << GEN6_GS_SAMPLER_COUNT_SHIFT) |
-		(0 << GEN6_GS_BINDING_TABLE_ENTRY_COUNT_SHIFT));
-      OUT_BATCH(0); /* scratch space base offset */
-      OUT_BATCH((1 << GEN6_GS_DISPATCH_START_GRF_SHIFT) |
-		(brw->gs.prog_data->urb_read_length << GEN6_GS_URB_READ_LENGTH_SHIFT) |
-		(0 << GEN6_GS_URB_ENTRY_READ_OFFSET_SHIFT));
-      OUT_BATCH((0 << GEN6_GS_MAX_THREADS_SHIFT) |
-		GEN6_GS_STATISTICS_ENABLE |
-		GEN6_GS_RENDERING_ENABLE);
-      OUT_BATCH(GEN6_GS_ENABLE);
-      ADVANCE_BATCH();
-   } else {
-      BEGIN_BATCH(7);
-      OUT_BATCH(_3DSTATE_GS << 16 | (7 - 2));
-      OUT_BATCH(0); /* prog_bo */
-      OUT_BATCH((0 << GEN6_GS_SAMPLER_COUNT_SHIFT) |
-		(0 << GEN6_GS_BINDING_TABLE_ENTRY_COUNT_SHIFT));
-      OUT_BATCH(0); /* scratch space base offset */
-      OUT_BATCH((1 << GEN6_GS_DISPATCH_START_GRF_SHIFT) |
-		(0 << GEN6_GS_URB_READ_LENGTH_SHIFT) |
-		(0 << GEN6_GS_URB_ENTRY_READ_OFFSET_SHIFT));
-      OUT_BATCH((0 << GEN6_GS_MAX_THREADS_SHIFT) |
-		GEN6_GS_STATISTICS_ENABLE |
-		GEN6_GS_RENDERING_ENABLE);
-      OUT_BATCH(0);
-      ADVANCE_BATCH();
-   }
+   // GS should never be used on Gen6.  Disable it.
+   assert(brw->gs.prog_bo == NULL);
+   BEGIN_BATCH(7);
+   OUT_BATCH(_3DSTATE_GS << 16 | (7 - 2));
+   OUT_BATCH(0); /* prog_bo */
+   OUT_BATCH((0 << GEN6_GS_SAMPLER_COUNT_SHIFT) |
+	     (0 << GEN6_GS_BINDING_TABLE_ENTRY_COUNT_SHIFT));
+   OUT_BATCH(0); /* scratch space base offset */
+   OUT_BATCH((1 << GEN6_GS_DISPATCH_START_GRF_SHIFT) |
+	     (0 << GEN6_GS_URB_READ_LENGTH_SHIFT) |
+	     (0 << GEN6_GS_URB_ENTRY_READ_OFFSET_SHIFT));
+   OUT_BATCH((0 << GEN6_GS_MAX_THREADS_SHIFT) |
+	     GEN6_GS_STATISTICS_ENABLE |
+	     GEN6_GS_RENDERING_ENABLE);
+   OUT_BATCH(0);
+   ADVANCE_BATCH();
 }
 
 const struct brw_tracked_state gen6_gs_state = {
-- 
1.7.4.4