gallium: add start_slot parameter to set_vertex_buffers

This allows updating only a subrange of buffer bindings.

set_vertex_buffers(pipe, start_slot, count, NULL) unbinds buffers in that
range. Binding NULL resources unbinds buffers too (both buffer and user_buffer
must be NULL).

The meta ops are adapted to only save, change, and restore the single slot
they use. The cso_context can save and restore only one vertex buffer slot.
The clients can query which one it is using cso_get_aux_vertex_buffer_slot.
It's currently set to 0. (the Draw module breaks if it's set to non-zero)

It should decrease the CPU overhead when using a lot of meta ops, but
the drivers must be able to treat each vertex buffer slot as a separate
state (only r600g does so at the moment).

I can imagine this also being useful for optimizing some OpenGL use cases.

Reviewed-by: Brian Paul <[email protected]>

12 files changed, 336 insertions, 164 deletions

diff --git a/src/gallium/auxiliary/util/u_blit.c b/src/gallium/auxiliary/util/u_blit.c
index bf1c392cd41..ab1549e2de6 100644
--- a/src/gallium/auxiliary/util/u_blit.c
+++ b/src/gallium/auxiliary/util/u_blit.c
@@ -133,7 +133,7 @@ util_create_blit(struct pipe_context *pipe, struct cso_context *cso)
    for (i = 0; i < 2; i++) {
       ctx->velem[i].src_offset = i * 4 * sizeof(float);
       ctx->velem[i].instance_divisor = 0;
-      ctx->velem[i].vertex_buffer_index = 0;
+      ctx->velem[i].vertex_buffer_index = cso_get_aux_vertex_buffer_slot(cso);
       ctx->velem[i].src_format = PIPE_FORMAT_R32G32B32A32_FLOAT;
    }
 
@@ -665,7 +665,7 @@ util_blit_pixels(struct blit_state *ctx,
    cso_save_vertex_shader(ctx->cso);
    cso_save_geometry_shader(ctx->cso);
    cso_save_vertex_elements(ctx->cso);
-   cso_save_vertex_buffers(ctx->cso);
+   cso_save_aux_vertex_buffer_slot(ctx->cso);
 
    /* set misc state we care about */
    if (writemask)
@@ -776,7 +776,9 @@ util_blit_pixels(struct blit_state *ctx,
                                   z);
 
    if (ctx->vbuf) {
-      util_draw_vertex_buffer(ctx->pipe, ctx->cso, ctx->vbuf, offset,
+      util_draw_vertex_buffer(ctx->pipe, ctx->cso, ctx->vbuf,
+                              cso_get_aux_vertex_buffer_slot(ctx->cso),
+                              offset,
                               PIPE_PRIM_TRIANGLE_FAN,
                               4,  /* verts */
                               2); /* attribs/vert */
@@ -795,7 +797,7 @@ util_blit_pixels(struct blit_state *ctx,
    cso_restore_vertex_shader(ctx->cso);
    cso_restore_geometry_shader(ctx->cso);
    cso_restore_vertex_elements(ctx->cso);
-   cso_restore_vertex_buffers(ctx->cso);
+   cso_restore_aux_vertex_buffer_slot(ctx->cso);
    cso_restore_stream_outputs(ctx->cso);
 
    pipe_sampler_view_reference(&sampler_view, NULL);
@@ -869,7 +871,7 @@ util_blit_pixels_tex(struct blit_state *ctx,
    cso_save_vertex_shader(ctx->cso);
    cso_save_geometry_shader(ctx->cso);
    cso_save_vertex_elements(ctx->cso);
-   cso_save_vertex_buffers(ctx->cso);
+   cso_save_aux_vertex_buffer_slot(ctx->cso);
 
    /* set misc state we care about */
    cso_set_blend(ctx->cso, &ctx->blend_write_color);
@@ -923,8 +925,9 @@ util_blit_pixels_tex(struct blit_state *ctx,
                                   s0, t0, s1, t1,
                                   z);
 
-   util_draw_vertex_buffer(ctx->pipe, ctx->cso,
-                           ctx->vbuf, offset,
+   util_draw_vertex_buffer(ctx->pipe, ctx->cso, ctx->vbuf,
+                           cso_get_aux_vertex_buffer_slot(ctx->cso),
+                           offset,
                            PIPE_PRIM_TRIANGLE_FAN,
                            4,  /* verts */
                            2); /* attribs/vert */
@@ -942,6 +945,6 @@ util_blit_pixels_tex(struct blit_state *ctx,
    cso_restore_vertex_shader(ctx->cso);
    cso_restore_geometry_shader(ctx->cso);
    cso_restore_vertex_elements(ctx->cso);
-   cso_restore_vertex_buffers(ctx->cso);
+   cso_restore_aux_vertex_buffer_slot(ctx->cso);
    cso_restore_stream_outputs(ctx->cso);
 }
diff --git a/src/gallium/auxiliary/util/u_blitter.c b/src/gallium/auxiliary/util/u_blitter.c
index f4ac4aa8685..bb784d6b370 100644
--- a/src/gallium/auxiliary/util/u_blitter.c
+++ b/src/gallium/auxiliary/util/u_blitter.c
@@ -158,7 +158,6 @@ struct blitter_context *util_blitter_create(struct pipe_context *pipe)
    ctx->base.saved_fb_state.nr_cbufs = ~0;
    ctx->base.saved_num_sampler_views = ~0;
    ctx->base.saved_num_sampler_states = ~0;
-   ctx->base.saved_num_vertex_buffers = ~0;
    ctx->base.saved_num_so_targets = ~0;
 
    ctx->has_geometry_shader =
@@ -241,11 +240,14 @@ struct blitter_context *util_blitter_create(struct pipe_context *pipe)
       ctx->rs_discard_state = pipe->create_rasterizer_state(pipe, &rs_state);
    }
 
+   ctx->base.vb_slot = 0; /* 0 for now */
+
    /* vertex elements states */
    memset(&velem[0], 0, sizeof(velem[0]) * 2);
    for (i = 0; i < 2; i++) {
       velem[i].src_offset = i * 4 * sizeof(float);
       velem[i].src_format = PIPE_FORMAT_R32G32B32A32_FLOAT;
+      velem[i].vertex_buffer_index = ctx->base.vb_slot;
    }
    ctx->velem_state = pipe->create_vertex_elements_state(pipe, 2, &velem[0]);
 
@@ -253,20 +255,25 @@ struct blitter_context *util_blitter_create(struct pipe_context *pipe)
       memset(&velem[0], 0, sizeof(velem[0]) * 2);
       velem[0].src_offset = 0;
       velem[0].src_format = PIPE_FORMAT_R32G32B32A32_FLOAT;
+      velem[0].vertex_buffer_index = ctx->base.vb_slot;
       velem[1].src_offset = 4 * sizeof(float);
       velem[1].src_format = PIPE_FORMAT_R32G32B32A32_SINT;
+      velem[1].vertex_buffer_index = ctx->base.vb_slot;
       ctx->velem_sint_state = pipe->create_vertex_elements_state(pipe, 2, &velem[0]);
 
       memset(&velem[0], 0, sizeof(velem[0]) * 2);
       velem[0].src_offset = 0;
       velem[0].src_format = PIPE_FORMAT_R32G32B32A32_FLOAT;
+      velem[0].vertex_buffer_index = ctx->base.vb_slot;
       velem[1].src_offset = 4 * sizeof(float);
       velem[1].src_format = PIPE_FORMAT_R32G32B32A32_UINT;
+      velem[1].vertex_buffer_index = ctx->base.vb_slot;
       ctx->velem_uint_state = pipe->create_vertex_elements_state(pipe, 2, &velem[0]);
    }
 
    if (ctx->has_stream_out) {
       velem[0].src_format = PIPE_FORMAT_R32_UINT;
+      velem[0].vertex_buffer_index = ctx->base.vb_slot;
       ctx->velem_state_readbuf = pipe->create_vertex_elements_state(pipe, 1, &velem[0]);
    }
 
@@ -387,7 +394,6 @@ static void blitter_unset_running_flag(struct blitter_context_priv *ctx)
 
 static void blitter_check_saved_vertex_states(struct blitter_context_priv *ctx)
 {
-   assert(ctx->base.saved_num_vertex_buffers != ~0);
    assert(ctx->base.saved_velem_state != INVALID_PTR);
    assert(ctx->base.saved_vs != INVALID_PTR);
    assert(!ctx->has_geometry_shader || ctx->base.saved_gs != INVALID_PTR);
@@ -400,18 +406,10 @@ static void blitter_restore_vertex_states(struct blitter_context_priv *ctx)
    struct pipe_context *pipe = ctx->base.pipe;
    unsigned i;
 
-   /* Vertex buffers. */
-   pipe->set_vertex_buffers(pipe,
-                            ctx->base.saved_num_vertex_buffers,
-                            ctx->base.saved_vertex_buffers);
-
-   for (i = 0; i < ctx->base.saved_num_vertex_buffers; i++) {
-      if (ctx->base.saved_vertex_buffers[i].buffer) {
-         pipe_resource_reference(&ctx->base.saved_vertex_buffers[i].buffer,
-                                 NULL);
-      }
-   }
-   ctx->base.saved_num_vertex_buffers = ~0;
+   /* Vertex buffer. */
+   pipe->set_vertex_buffers(pipe, ctx->base.vb_slot, 1,
+                            &ctx->base.saved_vertex_buffer);
+   pipe_resource_reference(&ctx->base.saved_vertex_buffer.buffer, NULL);
 
    /* Vertex elements. */
    pipe->bind_vertex_elements_state(pipe, ctx->base.saved_velem_state);
@@ -935,8 +933,8 @@ static void blitter_draw(struct blitter_context_priv *ctx,
    u_upload_data(ctx->upload, 0, sizeof(ctx->vertices), ctx->vertices,
                  &offset, &buf);
    u_upload_unmap(ctx->upload);
-   util_draw_vertex_buffer(ctx->base.pipe, NULL, buf, offset,
-                           PIPE_PRIM_TRIANGLE_FAN, 4, 2);
+   util_draw_vertex_buffer(ctx->base.pipe, NULL, buf, ctx->base.vb_slot,
+                           offset, PIPE_PRIM_TRIANGLE_FAN, 4, 2);
    pipe_resource_reference(&buf, NULL);
 }
 
@@ -1687,7 +1685,7 @@ void util_blitter_copy_buffer(struct blitter_context *blitter,
    vb.buffer_offset = srcx;
    vb.stride = 4;
 
-   pipe->set_vertex_buffers(pipe, 1, &vb);
+   pipe->set_vertex_buffers(pipe, ctx->base.vb_slot, 1, &vb);
    pipe->bind_vertex_elements_state(pipe, ctx->velem_state_readbuf);
    pipe->bind_vs_state(pipe, ctx->vs_pos_only);
    if (ctx->has_geometry_shader)
diff --git a/src/gallium/auxiliary/util/u_blitter.h b/src/gallium/auxiliary/util/u_blitter.h
index c49faaad717..b96e68e9310 100644
--- a/src/gallium/auxiliary/util/u_blitter.h
+++ b/src/gallium/auxiliary/util/u_blitter.h
@@ -104,8 +104,8 @@ struct blitter_context
    unsigned saved_num_sampler_views;
    struct pipe_sampler_view *saved_sampler_views[PIPE_MAX_SAMPLERS];
 
-   unsigned saved_num_vertex_buffers;
-   struct pipe_vertex_buffer saved_vertex_buffers[PIPE_MAX_ATTRIBS];
+   unsigned vb_slot;
+   struct pipe_vertex_buffer saved_vertex_buffer;
 
    unsigned saved_num_so_targets;
    struct pipe_stream_output_target *saved_so_targets[PIPE_MAX_SO_BUFFERS];
@@ -466,17 +466,13 @@ util_blitter_save_fragment_sampler_views(struct blitter_context *blitter,
 }
 
 static INLINE void
-util_blitter_save_vertex_buffers(struct blitter_context *blitter,
-                                 unsigned num_vertex_buffers,
-                                 struct pipe_vertex_buffer *vertex_buffers)
+util_blitter_save_vertex_buffer_slot(struct blitter_context *blitter,
+                                     struct pipe_vertex_buffer *vertex_buffers)
 {
-   assert(num_vertex_buffers <= Elements(blitter->saved_vertex_buffers));
-
-   blitter->saved_num_vertex_buffers = 0;
-   util_copy_vertex_buffers(blitter->saved_vertex_buffers,
-                            (unsigned*)&blitter->saved_num_vertex_buffers,
-                            vertex_buffers,
-                            num_vertex_buffers);
+   pipe_resource_reference(&blitter->saved_vertex_buffer.buffer,
+                           vertex_buffers[blitter->vb_slot].buffer);
+   memcpy(&blitter->saved_vertex_buffer, &vertex_buffers[blitter->vb_slot],
+          sizeof(struct pipe_vertex_buffer));
 }
 
 static INLINE void
diff --git a/src/gallium/auxiliary/util/u_draw_quad.c b/src/gallium/auxiliary/util/u_draw_quad.c
index 81c4f107ea9..3fe324afa80 100644
--- a/src/gallium/auxiliary/util/u_draw_quad.c
+++ b/src/gallium/auxiliary/util/u_draw_quad.c
@@ -42,6 +42,7 @@ void
 util_draw_vertex_buffer(struct pipe_context *pipe,
                         struct cso_context *cso,
                         struct pipe_resource *vbuf,
+                        uint vbuf_slot,
                         uint offset,
                         uint prim_type,
                         uint num_verts,
@@ -60,10 +61,10 @@ util_draw_vertex_buffer(struct pipe_context *pipe,
    /* note: vertex elements already set by caller */
 
    if (cso) {
-      cso_set_vertex_buffers(cso, 1, &vbuffer);
+      cso_set_vertex_buffers(cso, vbuf_slot, 1, &vbuffer);
       cso_draw_arrays(cso, prim_type, 0, num_verts);
    } else {
-      pipe->set_vertex_buffers(pipe, 1, &vbuffer);
+      pipe->set_vertex_buffers(pipe, vbuf_slot, 1, &vbuffer);
       util_draw_arrays(pipe, prim_type, 0, num_verts);
    }
 }
@@ -86,7 +87,7 @@ util_draw_user_vertex_buffer(struct cso_context *cso, void *buffer,
 
    /* note: vertex elements already set by caller */
 
-   cso_set_vertex_buffers(cso, 1, &vbuffer);
+   cso_set_vertex_buffers(cso, 0, 1, &vbuffer);
    cso_draw_arrays(cso, prim_type, 0, num_verts);
 }
 
@@ -97,6 +98,7 @@ util_draw_user_vertex_buffer(struct cso_context *cso, void *buffer,
  */
 void 
 util_draw_texquad(struct pipe_context *pipe, struct cso_context *cso,
+                  uint vbuf_slot,
                   float x0, float y0, float x1, float y1, float z)
 {
    uint numAttribs = 2, i, j;
@@ -145,7 +147,8 @@ util_draw_texquad(struct pipe_context *pipe, struct cso_context *cso,
       goto out;
    pipe_buffer_write(pipe, vbuf, 0, vertexBytes, v);
 
-   util_draw_vertex_buffer(pipe, cso, vbuf, 0, PIPE_PRIM_TRIANGLE_FAN, 4, 2);
+   util_draw_vertex_buffer(pipe, cso, vbuf, vbuf_slot, 0,
+                           PIPE_PRIM_TRIANGLE_FAN, 4, 2);
 
 out:
    if (vbuf)
diff --git a/src/gallium/auxiliary/util/u_draw_quad.h b/src/gallium/auxiliary/util/u_draw_quad.h
index 2834a4a8115..cb17f4e4cb2 100644
--- a/src/gallium/auxiliary/util/u_draw_quad.h
+++ b/src/gallium/auxiliary/util/u_draw_quad.h
@@ -44,8 +44,9 @@ struct cso_context;
 
 extern void 
 util_draw_vertex_buffer(struct pipe_context *pipe, struct cso_context *cso,
-                        struct pipe_resource *vbuf, uint offset,
-                        uint num_attribs, uint num_verts, uint prim_type);
+                        struct pipe_resource *vbuf, uint vbuf_slot,
+                        uint offset, uint prim_type, uint num_attribs,
+                        uint num_verts);
 
 void
 util_draw_user_vertex_buffer(struct cso_context *cso, void *buffer,
@@ -53,6 +54,7 @@ util_draw_user_vertex_buffer(struct cso_context *cso, void *buffer,
 
 extern void 
 util_draw_texquad(struct pipe_context *pipe, struct cso_context *cso,
+                  uint vbuf_slot,
                   float x0, float y0, float x1, float y1, float z);
 
 
diff --git a/src/gallium/auxiliary/util/u_gen_mipmap.c b/src/gallium/auxiliary/util/u_gen_mipmap.c
index 4d8adb9f355..48ebdb9fa3d 100644
--- a/src/gallium/auxiliary/util/u_gen_mipmap.c
+++ b/src/gallium/auxiliary/util/u_gen_mipmap.c
@@ -1287,7 +1287,7 @@ util_create_gen_mipmap(struct pipe_context *pipe,
    for (i = 0; i < 2; i++) {
       ctx->velem[i].src_offset = i * 4 * sizeof(float);
       ctx->velem[i].instance_divisor = 0;
-      ctx->velem[i].vertex_buffer_index = 0;
+      ctx->velem[i].vertex_buffer_index = cso_get_aux_vertex_buffer_slot(cso);
       ctx->velem[i].src_format = PIPE_FORMAT_R32G32B32A32_FLOAT;
    }
 
@@ -1565,7 +1565,7 @@ util_gen_mipmap(struct gen_mipmap_state *ctx,
    cso_save_geometry_shader(ctx->cso);
    cso_save_viewport(ctx->cso);
    cso_save_vertex_elements(ctx->cso);
-   cso_save_vertex_buffers(ctx->cso);
+   cso_save_aux_vertex_buffer_slot(ctx->cso);
 
    /* bind our state */
    cso_set_blend(ctx->cso, is_depth ? &ctx->blend_keep_color :
@@ -1673,6 +1673,7 @@ util_gen_mipmap(struct gen_mipmap_state *ctx,
          util_draw_vertex_buffer(ctx->pipe,
                                  ctx->cso,
                                  ctx->vbuf,
+                                 cso_get_aux_vertex_buffer_slot(ctx->cso),
                                  offset,
                                  PIPE_PRIM_TRIANGLE_FAN,
                                  4,  /* verts */
@@ -1697,5 +1698,5 @@ util_gen_mipmap(struct gen_mipmap_state *ctx,
    cso_restore_viewport(ctx->cso);
    cso_restore_vertex_elements(ctx->cso);
    cso_restore_stream_outputs(ctx->cso);
-   cso_restore_vertex_buffers(ctx->cso);
+   cso_restore_aux_vertex_buffer_slot(ctx->cso);
 }
diff --git a/src/gallium/auxiliary/util/u_helpers.c b/src/gallium/auxiliary/util/u_helpers.c
new file mode 100644
index 00000000000..ac1edcdbb82
--- /dev/null
+++ b/src/gallium/auxiliary/util/u_helpers.c
@@ -0,0 +1,90 @@
+/**************************************************************************
+ *
+ * Copyright 2012 Marek Olšák <[email protected]>
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS AND/OR THEIR SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+#include "util/u_helpers.h"
+#include "util/u_inlines.h"
+
+/**
+ * This function is used to copy an array of pipe_vertex_buffer structures,
+ * while properly referencing the pipe_vertex_buffer::buffer member.
+ *
+ * enabled_buffers is updated such that the bits corresponding to the indices
+ * of disabled buffers are set to 0 and the enabled ones are set to 1.
+ *
+ * \sa util_copy_framebuffer_state
+ */
+void util_set_vertex_buffers_mask(struct pipe_vertex_buffer *dst,
+                                  uint32_t *enabled_buffers,
+                                  const struct pipe_vertex_buffer *src,
+                                  unsigned start_slot, unsigned count)
+{
+   unsigned i;
+   uint32_t bitmask = 0;
+
+   dst += start_slot;
+
+   if (src) {
+      for (i = 0; i < count; i++) {
+         if (src[i].buffer || src[i].user_buffer) {
+            bitmask |= 1 << i;
+         }
+         pipe_resource_reference(&dst[i].buffer, src[i].buffer);
+      }
+
+      /* Copy over the other members of pipe_vertex_buffer. */
+      memcpy(dst, src, count * sizeof(struct pipe_vertex_buffer));
+
+      *enabled_buffers &= ~(((1ull << count) - 1) << start_slot);
+      *enabled_buffers |= bitmask << start_slot;
+   }
+   else {
+      /* Unreference the buffers. */
+      for (i = 0; i < count; i++) {
+         pipe_resource_reference(&dst[i].buffer, NULL);
+         dst[i].user_buffer = NULL;
+      }
+
+      *enabled_buffers &= ~(((1ull << count) - 1) << start_slot);
+   }
+}
+
+/**
+ * Same as util_set_vertex_buffers_mask, but it only returns the number
+ * of bound buffers.
+ */
+void util_set_vertex_buffers_count(struct pipe_vertex_buffer *dst,
+                                   unsigned *dst_count,
+                                   const struct pipe_vertex_buffer *src,
+                                   unsigned start_slot, unsigned count)
+{
+   uint32_t enabled_buffers = (1ull << *dst_count) - 1;
+
+   util_set_vertex_buffers_mask(dst, &enabled_buffers, src, start_slot,
+                                count);
+
+   *dst_count = util_last_bit(enabled_buffers);
+}
diff --git a/src/gallium/auxiliary/util/u_helpers.h b/src/gallium/auxiliary/util/u_helpers.h
new file mode 100644
index 00000000000..09c7116fa6d
--- /dev/null
+++ b/src/gallium/auxiliary/util/u_helpers.h
@@ -0,0 +1,51 @@
+/**************************************************************************
+ *
+ * Copyright 2012 Marek Olšák <[email protected]>
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS AND/OR THEIR SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+#ifndef U_HELPERS_H
+#define U_HELPERS_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "pipe/p_state.h"
+
+void util_set_vertex_buffers_mask(struct pipe_vertex_buffer *dst,
+                                  uint32_t *enabled_buffers,
+                                  const struct pipe_vertex_buffer *src,
+                                  unsigned start_slot, unsigned count);
+
+void util_set_vertex_buffers_count(struct pipe_vertex_buffer *dst,
+                                   unsigned *dst_count,
+                                   const struct pipe_vertex_buffer *src,
+                                   unsigned start_slot, unsigned count);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/src/gallium/auxiliary/util/u_inlines.h b/src/gallium/auxiliary/util/u_inlines.h
index 5c6e7eb3234..3d68cf5400e 100644
--- a/src/gallium/auxiliary/util/u_inlines.h
+++ b/src/gallium/auxiliary/util/u_inlines.h
@@ -449,34 +449,6 @@ static INLINE boolean util_get_offset(
    }
 }
 
-/**
- * This function is used to copy an array of pipe_vertex_buffer structures,
- * while properly referencing the pipe_vertex_buffer::buffer member.
- *
- * \sa util_copy_framebuffer_state
- */
-static INLINE void util_copy_vertex_buffers(struct pipe_vertex_buffer *dst,
-                                            unsigned *dst_count,
-                                            const struct pipe_vertex_buffer *src,
-                                            unsigned src_count)
-{
-   unsigned i;
-
-   /* Reference the buffers of 'src' in 'dst'. */
-   for (i = 0; i < src_count; i++) {
-      pipe_resource_reference(&dst[i].buffer, src[i].buffer);
-   }
-   /* Unreference the rest of the buffers in 'dst'. */
-   for (; i < *dst_count; i++) {
-      pipe_resource_reference(&dst[i].buffer, NULL);
-   }
-
-   /* Update the size of 'dst' and copy over the other members
-    * of pipe_vertex_buffer. */
-   *dst_count = src_count;
-   memcpy(dst, src, src_count * sizeof(struct pipe_vertex_buffer));
-}
-
 static INLINE float
 util_get_min_point_size(const struct pipe_rasterizer_state *state)
 {
diff --git a/src/gallium/auxiliary/util/u_math.h b/src/gallium/auxiliary/util/u_math.h
index 4047bd9b016..607fbecb02f 100644
--- a/src/gallium/auxiliary/util/u_math.h
+++ b/src/gallium/auxiliary/util/u_math.h
@@ -482,12 +482,16 @@ unsigned ffs( unsigned u )
  */
 static INLINE unsigned util_last_bit(unsigned u)
 {
+#if defined(__GNUC__) && ((__GNUC__ * 100 + __GNUC_MINOR__) >= 304)
+   return u == 0 ? 0 : 32 - __builtin_clz(u);
+#else
    unsigned r = 0;
    while (u) {
        r++;
        u >>= 1;
    }
    return r;
+#endif
 }
 
 
diff --git a/src/gallium/auxiliary/util/u_vbuf.c b/src/gallium/auxiliary/util/u_vbuf.c
index 1cc83c3dd39..7fb492882f5 100644
--- a/src/gallium/auxiliary/util/u_vbuf.c
+++ b/src/gallium/auxiliary/util/u_vbuf.c
@@ -89,17 +89,17 @@ struct u_vbuf {
    /* This is what was set in set_vertex_buffers.
     * May contain user buffers. */
    struct pipe_vertex_buffer vertex_buffer[PIPE_MAX_ATTRIBS];
-   unsigned nr_vertex_buffers;
+   uint32_t enabled_vb_mask;
 
-   /* Saved vertex buffers. */
-   struct pipe_vertex_buffer vertex_buffer_saved[PIPE_MAX_ATTRIBS];
-   unsigned nr_vertex_buffers_saved;
+   /* Saved vertex buffer. */
+   unsigned aux_vertex_buffer_slot;
+   struct pipe_vertex_buffer aux_vertex_buffer_saved;
 
    /* Vertex buffers for the driver.
-    * There are no user buffers. */
+    * There are usually no user buffers. */
    struct pipe_vertex_buffer real_vertex_buffer[PIPE_MAX_ATTRIBS];
-   unsigned nr_real_vertex_buffers;
-   boolean vertex_buffers_dirty;
+   uint32_t dirty_real_vb_mask; /* which buffers are dirty since the last
+                                   call of set_vertex_buffers */
 
    /* The index buffer. */
    struct pipe_index_buffer index_buffer;
@@ -174,11 +174,12 @@ void u_vbuf_get_caps(struct pipe_screen *screen, struct u_vbuf_caps *caps)
 
 struct u_vbuf *
 u_vbuf_create(struct pipe_context *pipe,
-              struct u_vbuf_caps *caps)
+              struct u_vbuf_caps *caps, unsigned aux_vertex_buffer_index)
 {
    struct u_vbuf *mgr = CALLOC_STRUCT(u_vbuf);
 
    mgr->caps = *caps;
+   mgr->aux_vertex_buffer_slot = aux_vertex_buffer_index;
    mgr->pipe = pipe;
    mgr->cso_cache = cso_cache_create();
    mgr->translate_cache = translate_cache_create();
@@ -239,16 +240,20 @@ void u_vbuf_set_vertex_elements(struct u_vbuf *mgr, unsigned count,
 
 void u_vbuf_destroy(struct u_vbuf *mgr)
 {
+   struct pipe_screen *screen = mgr->pipe->screen;
    unsigned i;
+   unsigned num_vb = screen->get_shader_param(screen, PIPE_SHADER_VERTEX,
+                                              PIPE_SHADER_CAP_MAX_INPUTS);
 
-   mgr->pipe->set_vertex_buffers(mgr->pipe, 0, NULL);
+   mgr->pipe->set_vertex_buffers(mgr->pipe, 0, num_vb, NULL);
 
-   for (i = 0; i < mgr->nr_vertex_buffers; i++) {
+   for (i = 0; i < PIPE_MAX_ATTRIBS; i++) {
       pipe_resource_reference(&mgr->vertex_buffer[i].buffer, NULL);
    }
-   for (i = 0; i < mgr->nr_real_vertex_buffers; i++) {
+   for (i = 0; i < PIPE_MAX_ATTRIBS; i++) {
       pipe_resource_reference(&mgr->real_vertex_buffer[i].buffer, NULL);
    }
+   pipe_resource_reference(&mgr->aux_vertex_buffer_saved.buffer, NULL);
 
    translate_cache_destroy(mgr->translate_cache);
    u_upload_destroy(mgr->uploader);
@@ -267,39 +272,42 @@ u_vbuf_translate_buffers(struct u_vbuf *mgr, struct translate_key *key,
    struct pipe_transfer *vb_transfer[PIPE_MAX_ATTRIBS] = {0};
    struct pipe_resource *out_buffer = NULL;
    uint8_t *out_map;
-   unsigned i, out_offset;
+   unsigned out_offset, mask;
 
    /* Get a translate object. */
    tr = translate_cache_find(mgr->translate_cache, key);
 
    /* Map buffers we want to translate. */
-   for (i = 0; i < mgr->nr_vertex_buffers; i++) {
-      if (vb_mask & (1 << i)) {
-         struct pipe_vertex_buffer *vb = &mgr->vertex_buffer[i];
-         unsigned offset = vb->buffer_offset + vb->stride * start_vertex;
-         uint8_t *map;
+   mask = vb_mask;
+   while (mask) {
+      struct pipe_vertex_buffer *vb;
+      unsigned offset;
+      uint8_t *map;
+      unsigned i = u_bit_scan(&mask);
 
-         if (vb->user_buffer) {
-            map = (uint8_t*)vb->user_buffer + offset;
-         } else {
-            unsigned size = vb->stride ? num_vertices * vb->stride
-                                       : sizeof(double)*4;
+      vb = &mgr->vertex_buffer[i];
+      offset = vb->buffer_offset + vb->stride * start_vertex;
 
-            if (offset+size > vb->buffer->width0) {
-               size = vb->buffer->width0 - offset;
-            }
+      if (vb->user_buffer) {
+         map = (uint8_t*)vb->user_buffer + offset;
+      } else {
+         unsigned size = vb->stride ? num_vertices * vb->stride
+                                    : sizeof(double)*4;
 
-            map = pipe_buffer_map_range(mgr->pipe, vb->buffer, offset, size,
-                                        PIPE_TRANSFER_READ, &vb_transfer[i]);
+         if (offset+size > vb->buffer->width0) {
+            size = vb->buffer->width0 - offset;
          }
 
-         /* Subtract min_index so that indexing with the index buffer works. */
-         if (unroll_indices) {
-            map -= vb->stride * min_index;
-         }
+         map = pipe_buffer_map_range(mgr->pipe, vb->buffer, offset, size,
+                                     PIPE_TRANSFER_READ, &vb_transfer[i]);
+      }
 
-         tr->set_buffer(tr, i, map, vb->stride, ~0);
+      /* Subtract min_index so that indexing with the index buffer works. */
+      if (unroll_indices) {
+         map -= vb->stride * min_index;
       }
+
+      tr->set_buffer(tr, i, map, vb->stride, ~0);
    }
 
    /* Translate. */
@@ -354,7 +362,10 @@ u_vbuf_translate_buffers(struct u_vbuf *mgr, struct translate_key *key,
    }
 
    /* Unmap all buffers. */
-   for (i = 0; i < mgr->nr_vertex_buffers; i++) {
+   mask = vb_mask;
+   while (mask) {
+      unsigned i = u_bit_scan(&mask);
+
       if (vb_transfer[i]) {
          pipe_buffer_unmap(mgr->pipe, vb_transfer[i]);
       }
@@ -379,7 +390,7 @@ u_vbuf_translate_find_free_vb_slots(struct u_vbuf *mgr,
    /* Set the bit for each buffer which is incompatible, or isn't set. */
    uint32_t unused_vb_mask =
       mgr->ve->incompatible_vb_mask_all | mgr->incompatible_vb_mask |
-      ~((1 << mgr->nr_vertex_buffers) - 1);
+      ~mgr->enabled_vb_mask;
 
    memset(fallback_vbs, ~0, sizeof(fallback_vbs));
 
@@ -389,20 +400,21 @@ u_vbuf_translate_find_free_vb_slots(struct u_vbuf *mgr,
          uint32_t index;
 
          if (!unused_vb_mask) {
-            /* fail, reset the number to its original value */
-            mgr->nr_real_vertex_buffers = mgr->nr_vertex_buffers;
             return FALSE;
          }
 
          index = ffs(unused_vb_mask) - 1;
          fallback_vbs[type] = index;
-         if (index >= mgr->nr_real_vertex_buffers) {
-            mgr->nr_real_vertex_buffers = index + 1;
-         }
          /*printf("found slot=%i for type=%i\n", index, type);*/
       }
    }
 
+   for (type = 0; type < VB_NUM; type++) {
+      if (mask[type]) {
+         mgr->dirty_real_vb_mask |= 1 << fallback_vbs[type];
+      }
+   }
+
    memcpy(mgr->fallback_vbs, fallback_vbs, sizeof(fallback_vbs));
    return TRUE;
 }
@@ -568,9 +580,11 @@ static void u_vbuf_translate_end(struct u_vbuf *mgr)
       if (vb != ~0) {
          pipe_resource_reference(&mgr->real_vertex_buffer[vb].buffer, NULL);
          mgr->fallback_vbs[i] = ~0;
+
+         /* This will cause the buffer to be unbound in the driver later. */
+         mgr->dirty_real_vb_mask |= 1 << vb;
       }
    }
-   mgr->nr_real_vertex_buffers = mgr->nr_vertex_buffers;
 }
 
 #define FORMAT_REPLACE(what, withwhat) \
@@ -700,45 +714,77 @@ static void u_vbuf_delete_vertex_elements(struct u_vbuf *mgr, void *cso)
    FREE(ve);
 }
 
-void u_vbuf_set_vertex_buffers(struct u_vbuf *mgr, unsigned count,
+void u_vbuf_set_vertex_buffers(struct u_vbuf *mgr,
+                               unsigned start_slot, unsigned count,
                                const struct pipe_vertex_buffer *bufs)
 {
    unsigned i;
+   /* which buffers are enabled */
+   uint32_t enabled_vb_mask = 0;
+   /* which buffers are in user memory */
+   uint32_t user_vb_mask = 0;
+   /* which buffers are incompatible with the driver */
+   uint32_t incompatible_vb_mask = 0;
+   /* which buffers have a non-zero stride */
+   uint32_t nonzero_stride_vb_mask = 0;
+   uint32_t mask = ~(((1ull << count) - 1) << start_slot);
+
+   /* Zero out the bits we are going to rewrite completely. */
+   mgr->user_vb_mask &= mask;
+   mgr->incompatible_vb_mask &= mask;
+   mgr->nonzero_stride_vb_mask &= mask;
+   mgr->enabled_vb_mask &= mask;
+
+   if (!bufs) {
+      struct pipe_context *pipe = mgr->pipe;
+      /* Unbind. */
+      mgr->dirty_real_vb_mask &= mask;
 
-   mgr->user_vb_mask = 0;
-   mgr->incompatible_vb_mask = 0;
-   mgr->nonzero_stride_vb_mask = 0;
+      for (i = 0; i < count; i++) {
+         unsigned dst_index = start_slot + i;
+
+         pipe_resource_reference(&mgr->vertex_buffer[dst_index].buffer, NULL);
+         pipe_resource_reference(&mgr->real_vertex_buffer[dst_index].buffer,
+                                 NULL);
+      }
+
+      pipe->set_vertex_buffers(pipe, start_slot, count, NULL);
+      return;
+   }
 
    for (i = 0; i < count; i++) {
+      unsigned dst_index = start_slot + i;
       const struct pipe_vertex_buffer *vb = &bufs[i];
-      struct pipe_vertex_buffer *orig_vb = &mgr->vertex_buffer[i];
-      struct pipe_vertex_buffer *real_vb = &mgr->real_vertex_buffer[i];
+      struct pipe_vertex_buffer *orig_vb = &mgr->vertex_buffer[dst_index];
+      struct pipe_vertex_buffer *real_vb = &mgr->real_vertex_buffer[dst_index];
+
+      if (!vb->buffer && !vb->user_buffer) {
+         pipe_resource_reference(&orig_vb->buffer, NULL);
+         pipe_resource_reference(&real_vb->buffer, NULL);
+         real_vb->user_buffer = NULL;
+         continue;
+      }
 
       pipe_resource_reference(&orig_vb->buffer, vb->buffer);
       orig_vb->user_buffer = vb->user_buffer;
 
       real_vb->buffer_offset = orig_vb->buffer_offset = vb->buffer_offset;
       real_vb->stride = orig_vb->stride = vb->stride;
-      real_vb->user_buffer = NULL;
 
       if (vb->stride) {
-         mgr->nonzero_stride_vb_mask |= 1 << i;
-      }
-
-      if (!vb->buffer && !vb->user_buffer) {
-         pipe_resource_reference(&real_vb->buffer, NULL);
-         continue;
+         nonzero_stride_vb_mask |= 1 << dst_index;
       }
+      enabled_vb_mask |= 1 << dst_index;
 
       if ((!mgr->caps.buffer_offset_unaligned && vb->buffer_offset % 4 != 0) ||
           (!mgr->caps.buffer_stride_unaligned && vb->stride % 4 != 0)) {
-         mgr->incompatible_vb_mask |= 1 << i;
+         incompatible_vb_mask |= 1 << dst_index;
          pipe_resource_reference(&real_vb->buffer, NULL);
          continue;
       }
 
       if (!mgr->caps.user_vertex_buffers && vb->user_buffer) {
-         mgr->user_vb_mask |= 1 << i;
+         user_vb_mask |= 1 << dst_index;
          pipe_resource_reference(&real_vb->buffer, NULL);
          continue;
       }
@@ -747,16 +793,14 @@ void u_vbuf_set_vertex_buffers(struct u_vbuf *mgr, unsigned count,
       real_vb->user_buffer = vb->user_buffer;
    }
 
-   for (i = count; i < mgr->nr_vertex_buffers; i++) {
-      pipe_resource_reference(&mgr->vertex_buffer[i].buffer, NULL);
-   }
-   for (i = count; i < mgr->nr_real_vertex_buffers; i++) {
-      pipe_resource_reference(&mgr->real_vertex_buffer[i].buffer, NULL);
-   }
+   mgr->user_vb_mask |= user_vb_mask;
+   mgr->incompatible_vb_mask |= incompatible_vb_mask;
+   mgr->nonzero_stride_vb_mask |= nonzero_stride_vb_mask;
+   mgr->enabled_vb_mask |= enabled_vb_mask;
 
-   mgr->nr_vertex_buffers = count;
-   mgr->nr_real_vertex_buffers = count;
-   mgr->vertex_buffers_dirty = TRUE;
+   /* All changed buffers are marked as dirty, even the NULL ones,
+    * which will cause the NULL buffers to be unbound in the driver later. */
+   mgr->dirty_real_vb_mask |= ~mask;
 }
 
 void u_vbuf_set_index_buffer(struct u_vbuf *mgr,
@@ -782,7 +826,7 @@ u_vbuf_upload_buffers(struct u_vbuf *mgr,
 {
    unsigned i;
    unsigned nr_velems = mgr->ve->count;
-   unsigned nr_vbufs = mgr->nr_vertex_buffers;
+   unsigned nr_vbufs = util_last_bit(mgr->enabled_vb_mask);
    struct pipe_vertex_element *velems =
          mgr->using_translate ? mgr->fallback_velems : mgr->ve->ve;
    unsigned start_offset[PIPE_MAX_ATTRIBS];
@@ -978,6 +1022,19 @@ static void u_vbuf_get_minmax_index(struct pipe_context *pipe,
    }
 }
 
+static void u_vbuf_set_driver_vertex_buffers(struct u_vbuf *mgr)
+{
+   struct pipe_context *pipe = mgr->pipe;
+   unsigned start_slot, count;
+
+   start_slot = ffs(mgr->dirty_real_vb_mask) - 1;
+   count = util_last_bit(mgr->dirty_real_vb_mask >> start_slot);
+
+   pipe->set_vertex_buffers(pipe, start_slot, count,
+                            mgr->real_vertex_buffer + start_slot);
+   mgr->dirty_real_vb_mask = 0;
+}
+
 void u_vbuf_draw_vbo(struct u_vbuf *mgr, const struct pipe_draw_info *info)
 {
    struct pipe_context *pipe = mgr->pipe;
@@ -990,11 +1047,10 @@ void u_vbuf_draw_vbo(struct u_vbuf *mgr, const struct pipe_draw_info *info)
    if (!mgr->incompatible_vb_mask &&
        !mgr->ve->incompatible_elem_mask &&
        !user_vb_mask) {
+
       /* Set vertex buffers if needed. */
-      if (mgr->vertex_buffers_dirty) {
-         pipe->set_vertex_buffers(pipe, mgr->nr_real_vertex_buffers,
-                                  mgr->real_vertex_buffer);
-         mgr->vertex_buffers_dirty = FALSE;
+      if (mgr->dirty_real_vb_mask) {
+         u_vbuf_set_driver_vertex_buffers(mgr);
       }
 
       pipe->draw_vbo(pipe, info);
@@ -1062,6 +1118,7 @@ void u_vbuf_draw_vbo(struct u_vbuf *mgr, const struct pipe_draw_info *info)
    if (user_vb_mask) {
       u_vbuf_upload_buffers(mgr, start_vertex, num_vertices,
                             info->start_instance, info->instance_count);
+      mgr->dirty_real_vb_mask |= user_vb_mask;
    }
 
    /*
@@ -1086,8 +1143,7 @@ void u_vbuf_draw_vbo(struct u_vbuf *mgr, const struct pipe_draw_info *info)
    */
 
    u_upload_unmap(mgr->uploader);
-   pipe->set_vertex_buffers(pipe, mgr->nr_real_vertex_buffers,
-                            mgr->real_vertex_buffer);
+   u_vbuf_set_driver_vertex_buffers(mgr);
 
    if (unlikely(unroll_indices)) {
       struct pipe_draw_info new_info = *info;
@@ -1105,7 +1161,6 @@ void u_vbuf_draw_vbo(struct u_vbuf *mgr, const struct pipe_draw_info *info)
    if (mgr->using_translate) {
       u_vbuf_translate_end(mgr);
    }
-   mgr->vertex_buffers_dirty = TRUE;
 }
 
 void u_vbuf_save_vertex_elements(struct u_vbuf *mgr)
@@ -1126,22 +1181,18 @@ void u_vbuf_restore_vertex_elements(struct u_vbuf *mgr)
    mgr->ve_saved = NULL;
 }
 
-void u_vbuf_save_vertex_buffers(struct u_vbuf *mgr)
+void u_vbuf_save_aux_vertex_buffer_slot(struct u_vbuf *mgr)
 {
-   util_copy_vertex_buffers(mgr->vertex_buffer_saved,
-                            &mgr->nr_vertex_buffers_saved,
-                            mgr->vertex_buffer,
-                            mgr->nr_vertex_buffers);
+   struct pipe_vertex_buffer *vb =
+         &mgr->vertex_buffer[mgr->aux_vertex_buffer_slot];
+
+   pipe_resource_reference(&mgr->aux_vertex_buffer_saved.buffer, vb->buffer);
+   memcpy(&mgr->aux_vertex_buffer_saved, vb, sizeof(*vb));
 }
 
-void u_vbuf_restore_vertex_buffers(struct u_vbuf *mgr)
+void u_vbuf_restore_aux_vertex_buffer_slot(struct u_vbuf *mgr)
 {
-   unsigned i;
-
-   u_vbuf_set_vertex_buffers(mgr, mgr->nr_vertex_buffers_saved,
-                             mgr->vertex_buffer_saved);
-   for (i = 0; i < mgr->nr_vertex_buffers_saved; i++) {
-      pipe_resource_reference(&mgr->vertex_buffer_saved[i].buffer, NULL);
-   }
-   mgr->nr_vertex_buffers_saved = 0;
+   u_vbuf_set_vertex_buffers(mgr, mgr->aux_vertex_buffer_slot, 1,
+                             &mgr->aux_vertex_buffer_saved);
+   pipe_resource_reference(&mgr->aux_vertex_buffer_saved.buffer, NULL);
 }
diff --git a/src/gallium/auxiliary/util/u_vbuf.h b/src/gallium/auxiliary/util/u_vbuf.h
index 59eb59a1190..0f82271649d 100644
--- a/src/gallium/auxiliary/util/u_vbuf.h
+++ b/src/gallium/auxiliary/util/u_vbuf.h
@@ -64,14 +64,15 @@ void u_vbuf_get_caps(struct pipe_screen *screen, struct u_vbuf_caps *caps);
 
 struct u_vbuf *
 u_vbuf_create(struct pipe_context *pipe,
-              struct u_vbuf_caps *caps);
+              struct u_vbuf_caps *caps, unsigned aux_vertex_buffer_index);
 
 void u_vbuf_destroy(struct u_vbuf *mgr);
 
 /* State and draw functions. */
 void u_vbuf_set_vertex_elements(struct u_vbuf *mgr, unsigned count,
                                 const struct pipe_vertex_element *states);
-void u_vbuf_set_vertex_buffers(struct u_vbuf *mgr, unsigned count,
+void u_vbuf_set_vertex_buffers(struct u_vbuf *mgr,
+                               unsigned start_slot, unsigned count,
                                const struct pipe_vertex_buffer *bufs);
 void u_vbuf_set_index_buffer(struct u_vbuf *mgr,
                              const struct pipe_index_buffer *ib);
@@ -80,7 +81,7 @@ void u_vbuf_draw_vbo(struct u_vbuf *mgr, const struct pipe_draw_info *info);
 /* Save/restore functionality. */
 void u_vbuf_save_vertex_elements(struct u_vbuf *mgr);
 void u_vbuf_restore_vertex_elements(struct u_vbuf *mgr);
-void u_vbuf_save_vertex_buffers(struct u_vbuf *mgr);
-void u_vbuf_restore_vertex_buffers(struct u_vbuf *mgr);
+void u_vbuf_save_aux_vertex_buffer_slot(struct u_vbuf *mgr);
+void u_vbuf_restore_aux_vertex_buffer_slot(struct u_vbuf *mgr);
 
 #endif