i965: Use force_compat_profile driconf option
[mesa.git] / src / mesa / drivers / dri / i965 / gen6_sol.c
index cdd6e74c8652eaf680c9c7f450b61fd7c6f6ff77..bda015e6cc5b74961f7937a83c3b99160d80d600 100644 (file)
@@ -26,6 +26,7 @@
  * Code to initialize the binding table entries used by transform feedback.
  */
 
+#include "main/bufferobj.h"
 #include "main/macros.h"
 #include "brw_context.h"
 #include "intel_batchbuffer.h"
 static void
 gen6_update_sol_surfaces(struct brw_context *brw)
 {
-   struct gl_context *ctx = &brw->intel.ctx;
-   /* BRW_NEW_TRANSFORM_FEEDBACK */
-   struct gl_transform_feedback_object *xfb_obj =
-      ctx->TransformFeedback.CurrentObject;
-   /* BRW_NEW_VERTEX_PROGRAM */
-   const struct gl_shader_program *shaderprog =
-      ctx->Shader.CurrentVertexProgram;
-   const struct gl_transform_feedback_info *linked_xfb_info =
-      &shaderprog->LinkedTransformFeedback;
-   int i;
-
-   for (i = 0; i < BRW_MAX_SOL_BINDINGS; ++i) {
-      const int surf_index = SURF_INDEX_SOL_BINDING(i);
-      if (_mesa_is_xfb_active_and_unpaused(ctx) &&
-          i < linked_xfb_info->NumOutputs) {
+   struct gl_context *ctx = &brw->ctx;
+   bool xfb_active = _mesa_is_xfb_active_and_unpaused(ctx);
+   struct gl_transform_feedback_object *xfb_obj;
+   const struct gl_transform_feedback_info *linked_xfb_info = NULL;
+
+   if (xfb_active) {
+      /* BRW_NEW_TRANSFORM_FEEDBACK */
+      xfb_obj = ctx->TransformFeedback.CurrentObject;
+      linked_xfb_info = xfb_obj->program->sh.LinkedTransformFeedback;
+   }
+
+   for (int i = 0; i < BRW_MAX_SOL_BINDINGS; ++i) {
+      const int surf_index = BRW_GEN6_SOL_BINDING_START + i;
+      if (xfb_active && i < linked_xfb_info->NumOutputs) {
          unsigned buffer = linked_xfb_info->Outputs[i].OutputBuffer;
          unsigned buffer_offset =
             xfb_obj->Offset[buffer] / 4 +
             linked_xfb_info->Outputs[i].DstOffset;
-         brw_update_sol_surface(
-            brw, xfb_obj->Buffers[buffer], &brw->gs.surf_offset[surf_index],
-            linked_xfb_info->Outputs[i].NumComponents,
-            linked_xfb_info->BufferStride[buffer], buffer_offset);
+         if (brw->programs[MESA_SHADER_GEOMETRY]) {
+            brw_update_sol_surface(
+               brw, xfb_obj->Buffers[buffer],
+               &brw->gs.base.surf_offset[surf_index],
+               linked_xfb_info->Outputs[i].NumComponents,
+               linked_xfb_info->Buffers[buffer].Stride, buffer_offset);
+         } else {
+            brw_update_sol_surface(
+               brw, xfb_obj->Buffers[buffer],
+               &brw->ff_gs.surf_offset[surf_index],
+               linked_xfb_info->Outputs[i].NumComponents,
+               linked_xfb_info->Buffers[buffer].Stride, buffer_offset);
+         }
       } else {
-         brw->gs.surf_offset[surf_index] = 0;
+         if (!brw->programs[MESA_SHADER_GEOMETRY])
+            brw->ff_gs.surf_offset[surf_index] = 0;
+         else
+            brw->gs.base.surf_offset[surf_index] = 0;
       }
    }
 
-   brw->state.dirty.brw |= BRW_NEW_SURFACES;
+   brw->ctx.NewDriverState |= BRW_NEW_SURFACES;
 }
 
 const struct brw_tracked_state gen6_sol_surface = {
    .dirty = {
       .mesa = 0,
-      .brw = (BRW_NEW_BATCH |
-              BRW_NEW_VERTEX_PROGRAM |
-              BRW_NEW_TRANSFORM_FEEDBACK),
-      .cache = 0
+      .brw = BRW_NEW_BATCH |
+             BRW_NEW_BLORP |
+             BRW_NEW_TRANSFORM_FEEDBACK,
    },
    .emit = gen6_update_sol_surfaces,
 };
@@ -85,117 +96,426 @@ const struct brw_tracked_state gen6_sol_surface = {
 static void
 brw_gs_upload_binding_table(struct brw_context *brw)
 {
-   struct gl_context *ctx = &brw->intel.ctx;
-   /* BRW_NEW_VERTEX_PROGRAM */
-   const struct gl_shader_program *shaderprog =
-      ctx->Shader.CurrentVertexProgram;
-   bool has_surfaces = false;
    uint32_t *bind;
+   struct gl_context *ctx = &brw->ctx;
+   const struct gl_program *prog;
+   bool need_binding_table = false;
 
-   if (shaderprog) {
-      const struct gl_transform_feedback_info *linked_xfb_info =
-        &shaderprog->LinkedTransformFeedback;
-      /* Currently we only ever upload surfaces for SOL. */
-      has_surfaces = linked_xfb_info->NumOutputs != 0;
-   }
+   /* We have two scenarios here:
+    * 1) We are using a geometry shader only to implement transform feedback
+    *    for a vertex shader (brw->programs[MESA_SHADER_GEOMETRY] == NULL).
+    *    In this case, we only need surfaces for transform feedback in the
+    *    GS stage.
+    * 2) We have a user-provided geometry shader. In this case we may need
+    *    surfaces for transform feedback and/or other stuff, like textures,
+    *    in the GS stage.
+    */
 
-   /* Skip making a binding table if we don't have anything to put in it. */
-   if (!has_surfaces) {
-      if (brw->gs.bind_bo_offset != 0) {
-        brw->state.dirty.brw |= BRW_NEW_GS_BINDING_TABLE;
-        brw->gs.bind_bo_offset = 0;
+   if (!brw->programs[MESA_SHADER_GEOMETRY]) {
+      /* BRW_NEW_VERTEX_PROGRAM */
+      prog = ctx->_Shader->CurrentProgram[MESA_SHADER_VERTEX];
+      if (prog) {
+         /* Skip making a binding table if we don't have anything to put in it */
+         const struct gl_transform_feedback_info *linked_xfb_info =
+            prog->sh.LinkedTransformFeedback;
+         need_binding_table = linked_xfb_info->NumOutputs > 0;
+      }
+      if (!need_binding_table) {
+         if (brw->ff_gs.bind_bo_offset != 0) {
+            brw->ctx.NewDriverState |= BRW_NEW_BINDING_TABLE_POINTERS;
+            brw->ff_gs.bind_bo_offset = 0;
+         }
+         return;
       }
-      return;
-   }
 
-   /* Might want to calculate nr_surfaces first, to avoid taking up so much
-    * space for the binding table.
-    */
-   bind = brw_state_batch(brw, AUB_TRACE_BINDING_TABLE,
-                         sizeof(uint32_t) * BRW_MAX_GS_SURFACES,
-                         32, &brw->gs.bind_bo_offset);
+      /* Might want to calculate nr_surfaces first, to avoid taking up so much
+       * space for the binding table. Anyway, in this case we know that we only
+       * use BRW_MAX_SOL_BINDINGS surfaces at most.
+       */
+      bind = brw_state_batch(brw, sizeof(uint32_t) * BRW_MAX_SOL_BINDINGS,
+                             32, &brw->ff_gs.bind_bo_offset);
+
+      /* BRW_NEW_SURFACES */
+      memcpy(bind, brw->ff_gs.surf_offset,
+             BRW_MAX_SOL_BINDINGS * sizeof(uint32_t));
+   } else {
+      /* BRW_NEW_GEOMETRY_PROGRAM */
+      prog = ctx->_Shader->CurrentProgram[MESA_SHADER_GEOMETRY];
+      if (prog) {
+         /* Skip making a binding table if we don't have anything to put in it */
+         struct brw_stage_prog_data *prog_data = brw->gs.base.prog_data;
+         const struct gl_transform_feedback_info *linked_xfb_info =
+            prog->sh.LinkedTransformFeedback;
+         need_binding_table = linked_xfb_info->NumOutputs > 0 ||
+                              prog_data->binding_table.size_bytes > 0;
+      }
+      if (!need_binding_table) {
+         if (brw->gs.base.bind_bo_offset != 0) {
+            brw->gs.base.bind_bo_offset = 0;
+            brw->ctx.NewDriverState |= BRW_NEW_BINDING_TABLE_POINTERS;
+         }
+         return;
+      }
+
+      /* Might want to calculate nr_surfaces first, to avoid taking up so much
+       * space for the binding table.
+       */
+      bind = brw_state_batch(brw, sizeof(uint32_t) * BRW_MAX_SURFACES,
+                             32, &brw->gs.base.bind_bo_offset);
 
-   /* BRW_NEW_SURFACES */
-   memcpy(bind, brw->gs.surf_offset, BRW_MAX_GS_SURFACES * sizeof(uint32_t));
+      /* BRW_NEW_SURFACES */
+      memcpy(bind, brw->gs.base.surf_offset,
+             BRW_MAX_SURFACES * sizeof(uint32_t));
+   }
 
-   brw->state.dirty.brw |= BRW_NEW_GS_BINDING_TABLE;
+   brw->ctx.NewDriverState |= BRW_NEW_BINDING_TABLE_POINTERS;
 }
 
 const struct brw_tracked_state gen6_gs_binding_table = {
    .dirty = {
       .mesa = 0,
-      .brw = (BRW_NEW_BATCH |
-             BRW_NEW_VERTEX_PROGRAM |
-             BRW_NEW_SURFACES),
-      .cache = 0
+      .brw = BRW_NEW_BATCH |
+             BRW_NEW_BLORP |
+             BRW_NEW_GEOMETRY_PROGRAM |
+             BRW_NEW_VERTEX_PROGRAM |
+             BRW_NEW_SURFACES,
    },
    .emit = brw_gs_upload_binding_table,
 };
 
+struct gl_transform_feedback_object *
+brw_new_transform_feedback(struct gl_context *ctx, GLuint name)
+{
+   struct brw_context *brw = brw_context(ctx);
+   struct brw_transform_feedback_object *brw_obj =
+      CALLOC_STRUCT(brw_transform_feedback_object);
+   if (!brw_obj)
+      return NULL;
+
+   _mesa_init_transform_feedback_object(&brw_obj->base, name);
+
+   brw_obj->offset_bo =
+      brw_bo_alloc(brw->bufmgr, "transform feedback offsets", 16,
+                   BRW_MEMZONE_OTHER);
+   brw_obj->prim_count_bo =
+      brw_bo_alloc(brw->bufmgr, "xfb primitive counts", 16384,
+                   BRW_MEMZONE_OTHER);
+
+   return &brw_obj->base;
+}
+
+void
+brw_delete_transform_feedback(struct gl_context *ctx,
+                              struct gl_transform_feedback_object *obj)
+{
+   struct brw_transform_feedback_object *brw_obj =
+      (struct brw_transform_feedback_object *) obj;
+
+   brw_bo_unreference(brw_obj->offset_bo);
+   brw_bo_unreference(brw_obj->prim_count_bo);
+
+   _mesa_delete_transform_feedback_object(ctx, obj);
+}
+
+/**
+ * Tally the number of primitives generated so far.
+ *
+ * The buffer contains a series of pairs:
+ * (<start0, start1, start2, start3>, <end0, end1, end2, end3>) ;
+ * (<start0, start1, start2, start3>, <end0, end1, end2, end3>) ;
+ *
+ * For each stream, we subtract the pair of values (end - start) to get the
+ * number of primitives generated during one section.  We accumulate these
+ * values, adding them up to get the total number of primitives generated.
+ *
+ * Note that we expose one stream pre-Gen7, so the above is just (start, end).
+ */
+static void
+aggregate_transform_feedback_counter(
+   struct brw_context *brw,
+   struct brw_bo *bo,
+   struct brw_transform_feedback_counter *counter)
+{
+   const unsigned streams = brw->ctx.Const.MaxVertexStreams;
+
+   /* If the current batch is still contributing to the number of primitives
+    * generated, flush it now so the results will be present when mapped.
+    */
+   if (brw_batch_references(&brw->batch, bo))
+      intel_batchbuffer_flush(brw);
+
+   if (unlikely(brw->perf_debug && brw_bo_busy(bo)))
+      perf_debug("Stalling for # of transform feedback primitives written.\n");
+
+   uint64_t *prim_counts = brw_bo_map(brw, bo, MAP_READ);
+   prim_counts += counter->bo_start * streams;
+
+   for (unsigned i = counter->bo_start; i + 1 < counter->bo_end; i += 2) {
+      for (unsigned s = 0; s < streams; s++)
+         counter->accum[s] += prim_counts[streams + s] - prim_counts[s];
+
+      prim_counts += 2 * streams;
+   }
+
+   brw_bo_unmap(bo);
+
+   /* We've already gathered up the old data; we can safely overwrite it now. */
+   counter->bo_start = counter->bo_end = 0;
+}
+
+/**
+ * Store the SO_NUM_PRIMS_WRITTEN counters for each stream (4 uint64_t values)
+ * to prim_count_bo.
+ *
+ * If prim_count_bo is out of space, gather up the results so far into
+ * prims_generated[] and allocate a new buffer with enough space.
+ *
+ * The number of primitives written is used to compute the number of vertices
+ * written to a transform feedback stream, which is required to implement
+ * DrawTransformFeedback().
+ */
+void
+brw_save_primitives_written_counters(struct brw_context *brw,
+                                     struct brw_transform_feedback_object *obj)
+{
+   const struct gen_device_info *devinfo = &brw->screen->devinfo;
+   const struct gl_context *ctx = &brw->ctx;
+   const int streams = ctx->Const.MaxVertexStreams;
+
+   assert(obj->prim_count_bo != NULL);
+
+   /* Check if there's enough space for a new pair of four values. */
+   if ((obj->counter.bo_end + 2) * streams * sizeof(uint64_t) >=
+       obj->prim_count_bo->size) {
+      aggregate_transform_feedback_counter(brw, obj->prim_count_bo,
+                                           &obj->previous_counter);
+      aggregate_transform_feedback_counter(brw, obj->prim_count_bo,
+                                           &obj->counter);
+   }
+
+   /* Flush any drawing so that the counters have the right values. */
+   brw_emit_mi_flush(brw);
+
+   /* Emit MI_STORE_REGISTER_MEM commands to write the values. */
+   if (devinfo->gen >= 7) {
+      for (int i = 0; i < streams; i++) {
+         int offset = (streams * obj->counter.bo_end + i) * sizeof(uint64_t);
+         brw_store_register_mem64(brw, obj->prim_count_bo,
+                                  GEN7_SO_NUM_PRIMS_WRITTEN(i),
+                                  offset);
+      }
+   } else {
+      brw_store_register_mem64(brw, obj->prim_count_bo,
+                               GEN6_SO_NUM_PRIMS_WRITTEN,
+                               obj->counter.bo_end * sizeof(uint64_t));
+   }
+
+   /* Update where to write data to. */
+   obj->counter.bo_end++;
+}
+
+static void
+compute_vertices_written_so_far(struct brw_context *brw,
+                                struct brw_transform_feedback_object *obj,
+                                struct brw_transform_feedback_counter *counter,
+                                uint64_t *vertices_written)
+{
+   const struct gl_context *ctx = &brw->ctx;
+   unsigned vertices_per_prim = 0;
+
+   switch (obj->primitive_mode) {
+   case GL_POINTS:
+      vertices_per_prim = 1;
+      break;
+   case GL_LINES:
+      vertices_per_prim = 2;
+      break;
+   case GL_TRIANGLES:
+      vertices_per_prim = 3;
+      break;
+   default:
+      unreachable("Invalid transform feedback primitive mode.");
+   }
+
+   /* Get the number of primitives generated. */
+   aggregate_transform_feedback_counter(brw, obj->prim_count_bo, counter);
+
+   for (int i = 0; i < ctx->Const.MaxVertexStreams; i++) {
+      vertices_written[i] = vertices_per_prim * counter->accum[i];
+   }
+}
+
+/**
+ * Compute the number of vertices written by the last transform feedback
+ * begin/end block.
+ */
+static void
+compute_xfb_vertices_written(struct brw_context *brw,
+                             struct brw_transform_feedback_object *obj)
+{
+   if (obj->vertices_written_valid || !obj->base.EndedAnytime)
+      return;
+
+   compute_vertices_written_so_far(brw, obj, &obj->previous_counter,
+                                   obj->vertices_written);
+   obj->vertices_written_valid = true;
+}
+
+/**
+ * GetTransformFeedbackVertexCount() driver hook.
+ *
+ * Returns the number of vertices written to a particular stream by the last
+ * Begin/EndTransformFeedback block.  Used to implement DrawTransformFeedback().
+ */
+GLsizei
+brw_get_transform_feedback_vertex_count(struct gl_context *ctx,
+                                        struct gl_transform_feedback_object *obj,
+                                        GLuint stream)
+{
+   struct brw_context *brw = brw_context(ctx);
+   struct brw_transform_feedback_object *brw_obj =
+      (struct brw_transform_feedback_object *) obj;
+
+   assert(obj->EndedAnytime);
+   assert(stream < ctx->Const.MaxVertexStreams);
+
+   compute_xfb_vertices_written(brw, brw_obj);
+   return brw_obj->vertices_written[stream];
+}
+
 void
 brw_begin_transform_feedback(struct gl_context *ctx, GLenum mode,
                             struct gl_transform_feedback_object *obj)
 {
    struct brw_context *brw = brw_context(ctx);
-   struct intel_context *intel = &brw->intel;
-   const struct gl_shader_program *vs_prog =
-      ctx->Shader.CurrentVertexProgram;
-   const struct gl_transform_feedback_info *linked_xfb_info =
-      &vs_prog->LinkedTransformFeedback;
+   const struct gl_program *prog;
+   const struct gl_transform_feedback_info *linked_xfb_info;
    struct gl_transform_feedback_object *xfb_obj =
       ctx->TransformFeedback.CurrentObject;
+   struct brw_transform_feedback_object *brw_obj =
+      (struct brw_transform_feedback_object *) xfb_obj;
+
+   assert(brw->screen->devinfo.gen == 6);
+
+   if (ctx->_Shader->CurrentProgram[MESA_SHADER_GEOMETRY]) {
+      /* BRW_NEW_GEOMETRY_PROGRAM */
+      prog = ctx->_Shader->CurrentProgram[MESA_SHADER_GEOMETRY];
+   } else {
+      /* BRW_NEW_VERTEX_PROGRAM */
+      prog = ctx->_Shader->CurrentProgram[MESA_SHADER_VERTEX];
+   }
+   linked_xfb_info = prog->sh.LinkedTransformFeedback;
 
    /* Compute the maximum number of vertices that we can write without
     * overflowing any of the buffers currently being used for feedback.
     */
-   unsigned max_index
-      = _mesa_compute_max_transform_feedback_vertices(xfb_obj,
+   brw_obj->max_index
+      = _mesa_compute_max_transform_feedback_vertices(ctx, xfb_obj,
                                                       linked_xfb_info);
 
-   if (intel->gen == 6) {
-      /* Initialize the SVBI 0 register to zero and set the maximum index. */
+   /* Initialize the SVBI 0 register to zero and set the maximum index. */
+   BEGIN_BATCH(4);
+   OUT_BATCH(_3DSTATE_GS_SVB_INDEX << 16 | (4 - 2));
+   OUT_BATCH(0); /* SVBI 0 */
+   OUT_BATCH(0); /* starting index */
+   OUT_BATCH(brw_obj->max_index);
+   ADVANCE_BATCH();
+
+   /* Initialize the rest of the unused streams to sane values.  Otherwise,
+    * they may indicate that there is no room to write data and prevent
+    * anything from happening at all.
+    */
+   for (int i = 1; i < 4; i++) {
       BEGIN_BATCH(4);
       OUT_BATCH(_3DSTATE_GS_SVB_INDEX << 16 | (4 - 2));
-      OUT_BATCH(0); /* SVBI 0 */
+      OUT_BATCH(i << SVB_INDEX_SHIFT);
       OUT_BATCH(0); /* starting index */
-      OUT_BATCH(max_index);
+      OUT_BATCH(0xffffffff);
       ADVANCE_BATCH();
-
-      /* Initialize the rest of the unused streams to sane values.  Otherwise,
-       * they may indicate that there is no room to write data and prevent
-       * anything from happening at all.
-       */
-      for (int i = 1; i < 4; i++) {
-         BEGIN_BATCH(4);
-         OUT_BATCH(_3DSTATE_GS_SVB_INDEX << 16 | (4 - 2));
-         OUT_BATCH(i << SVB_INDEX_SHIFT);
-         OUT_BATCH(0); /* starting index */
-         OUT_BATCH(0xffffffff);
-         ADVANCE_BATCH();
-      }
-   } else if (intel->gen >= 7) {
-      /* Reset the SOL buffer offset register. */
-      for (int i = 0; i < 4; i++) {
-         BEGIN_BATCH(3);
-         OUT_BATCH(MI_LOAD_REGISTER_IMM | (3 - 2));
-         OUT_BATCH(GEN7_SO_WRITE_OFFSET(i));
-         OUT_BATCH(0);
-         ADVANCE_BATCH();
-      }
    }
+
+   /* Store the starting value of the SO_NUM_PRIMS_WRITTEN counters. */
+   brw_save_primitives_written_counters(brw, brw_obj);
+
+   brw_obj->primitive_mode = mode;
 }
 
 void
 brw_end_transform_feedback(struct gl_context *ctx,
                            struct gl_transform_feedback_object *obj)
 {
-   /* After EndTransformFeedback, it's likely that the client program will try
-    * to draw using the contents of the transform feedback buffer as vertex
-    * input.  In order for this to work, we need to flush the data through at
-    * least the GS stage of the pipeline, and flush out the render cache.  For
-    * simplicity, just do a full flush.
+   struct brw_context *brw = brw_context(ctx);
+   struct brw_transform_feedback_object *brw_obj =
+      (struct brw_transform_feedback_object *) obj;
+
+   /* Store the ending value of the SO_NUM_PRIMS_WRITTEN counters. */
+   if (!obj->Paused)
+      brw_save_primitives_written_counters(brw, brw_obj);
+
+   /* We've reached the end of a transform feedback begin/end block.  This
+    * means that future DrawTransformFeedback() calls will need to pick up the
+    * results of the current counter, and that it's time to roll back the
+    * current primitive counter to zero.
+    */
+   brw_obj->previous_counter = brw_obj->counter;
+   brw_reset_transform_feedback_counter(&brw_obj->counter);
+
+   /* EndTransformFeedback() means that we need to update the number of
+    * vertices written.  Since it's only necessary if DrawTransformFeedback()
+    * is called and it means mapping a buffer object, we delay computing it
+    * until it's absolutely necessary to try and avoid stalls.
+    */
+   brw_obj->vertices_written_valid = false;
+}
+
+void
+brw_pause_transform_feedback(struct gl_context *ctx,
+                             struct gl_transform_feedback_object *obj)
+{
+   struct brw_context *brw = brw_context(ctx);
+   struct brw_transform_feedback_object *brw_obj =
+      (struct brw_transform_feedback_object *) obj;
+
+   /* Store the temporary ending value of the SO_NUM_PRIMS_WRITTEN counters.
+    * While this operation is paused, other transform feedback actions may
+    * occur, which will contribute to the counters.  We need to exclude that
+    * from our counts.
     */
+   brw_save_primitives_written_counters(brw, brw_obj);
+}
+
+void
+brw_resume_transform_feedback(struct gl_context *ctx,
+                              struct gl_transform_feedback_object *obj)
+{
    struct brw_context *brw = brw_context(ctx);
-   struct intel_context *intel = &brw->intel;
-   intel_batchbuffer_emit_mi_flush(intel);
+   struct brw_transform_feedback_object *brw_obj =
+      (struct brw_transform_feedback_object *) obj;
+
+   /* Reload SVBI 0 with the count of vertices written so far. */
+   uint64_t svbi;
+   compute_vertices_written_so_far(brw, brw_obj, &brw_obj->counter, &svbi);
+
+   BEGIN_BATCH(4);
+   OUT_BATCH(_3DSTATE_GS_SVB_INDEX << 16 | (4 - 2));
+   OUT_BATCH(0); /* SVBI 0 */
+   OUT_BATCH((uint32_t) svbi); /* starting index */
+   OUT_BATCH(brw_obj->max_index);
+   ADVANCE_BATCH();
+
+   /* Initialize the rest of the unused streams to sane values.  Otherwise,
+    * they may indicate that there is no room to write data and prevent
+    * anything from happening at all.
+    */
+   for (int i = 1; i < 4; i++) {
+      BEGIN_BATCH(4);
+      OUT_BATCH(_3DSTATE_GS_SVB_INDEX << 16 | (4 - 2));
+      OUT_BATCH(i << SVB_INDEX_SHIFT);
+      OUT_BATCH(0); /* starting index */
+      OUT_BATCH(0xffffffff);
+      ADVANCE_BATCH();
+   }
+
+   /* Store the new starting value of the SO_NUM_PRIMS_WRITTEN counters. */
+   brw_save_primitives_written_counters(brw, brw_obj);
 }