gallium/svga: Upload only parts of user-buffers that we actually use

Stream user buffer contents rather than trying to maintain persistent
host / hardware copies.
Resulting negative array offsets are not allowed by the hardware,
(well, at least not according to header files), so adjust index bias
to make all array offsets positive.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>

1 files changed, 52 insertions, 67 deletions

diff --git a/src/gallium/drivers/svga/svga_state_vdecl.c b/src/gallium/drivers/svga/svga_state_vdecl.c
index 7c393a1..2375a02 100644
--- a/src/gallium/drivers/svga/svga_state_vdecl.c
+++ b/src/gallium/drivers/svga/svga_state_vdecl.c
@@ -38,57 +38,6 @@
 #include "svga_hw_reg.h"
 
 
-static int
-upload_user_buffers( struct svga_context *svga )
-{
-   enum pipe_error ret = PIPE_OK;
-   int i;
-   int nr;
-
-   if (0) 
-      debug_printf("%s: %d\n", __FUNCTION__, svga->curr.num_vertex_buffers);
-
-   nr = svga->curr.num_vertex_buffers;
-
-   for (i = 0; i < nr; i++) 
-   {
-      if (svga_buffer_is_user_buffer(svga->curr.vb[i].buffer))
-      {
-         struct svga_buffer *buffer = svga_buffer(svga->curr.vb[i].buffer);
-
-         if (!buffer->uploaded.buffer) {
-            boolean flushed;
-            ret = u_upload_buffer( svga->upload_vb,
-                                   0, 0,
-                                   buffer->b.b.width0,
-                                   &buffer->b.b,
-                                   &buffer->uploaded.offset,
-                                   &buffer->uploaded.buffer,
-                                   &flushed);
-            if (ret)
-               return ret;
-
-            if (0)
-               debug_printf("%s: %d: orig buf %p upl buf %p ofs %d sz %d\n",
-                            __FUNCTION__,
-                            i,
-                            buffer,
-                            buffer->uploaded.buffer,
-                            buffer->uploaded.offset,
-                            buffer->b.b.width0);
-         }
-
-         svga->curr.vb[i].buffer_offset = buffer->uploaded.offset;
-      }
-   }
-
-   if (0)
-      debug_printf("%s: DONE\n", __FUNCTION__);
-
-   return ret;
-}
-
-
 /***********************************************************************
  */
 
@@ -99,6 +48,7 @@ static int emit_hw_vs_vdecl( struct svga_context *svga,
    const struct pipe_vertex_element *ve = svga->curr.velems->velem;
    SVGA3dVertexDecl decl;
    unsigned i;
+   unsigned neg_bias = 0;
 
    assert(svga->curr.velems->count >=
           svga->curr.vs->base.info.file_count[TGSI_FILE_INPUT]);
@@ -106,12 +56,50 @@ static int emit_hw_vs_vdecl( struct svga_context *svga,
    svga_hwtnl_reset_vdecl( svga->hwtnl, 
                            svga->curr.velems->count );
 
+   /**
+    * We can't set the VDECL offset to something negative, so we
+    * must calculate a common negative additional index bias, and modify
+    * the VDECL offsets accordingly so they *all* end up positive.
+    *
+    * Note that the exact value of the negative index bias is not that
+    * important, since we compensate for it when we calculate the vertex
+    * buffer offset below. The important thing is that all vertex buffer
+    * offsets remain positive.
+    *
+    * Note that we use a negative bias variable in order to make the
+    * rounding maths more easy to follow, and to avoid int / unsigned
+    * confusion.
+    */
+
    for (i = 0; i < svga->curr.velems->count; i++) {
-      const struct pipe_vertex_buffer *vb = &svga->curr.vb[ve[i].vertex_buffer_index];
+      const struct pipe_vertex_buffer *vb =
+         &svga->curr.vb[ve[i].vertex_buffer_index];
+      struct svga_buffer *buffer;
+      unsigned int offset = vb->buffer_offset + ve[i].src_offset;
+      unsigned tmp_neg_bias = 0;
+
+      if (!vb->buffer)
+         continue;
+
+      buffer = svga_buffer(vb->buffer);
+      if (buffer->source_offset > offset) {
+         tmp_neg_bias = buffer->source_offset - offset;
+         if (vb->stride)
+            tmp_neg_bias = (tmp_neg_bias + vb->stride - 1) / vb->stride;
+         neg_bias = MAX2(neg_bias, tmp_neg_bias);
+      }
+   }
+
+   for (i = 0; i < svga->curr.velems->count; i++) {
+      const struct pipe_vertex_buffer *vb =
+         &svga->curr.vb[ve[i].vertex_buffer_index];
       unsigned usage, index;
-      struct svga_buffer *buffer = svga_buffer(vb->buffer);
+      struct svga_buffer *buffer;
 
+      if (!vb->buffer)
+         continue;
 
+      buffer= svga_buffer(vb->buffer);
       svga_generate_vdecl_semantics( i, &usage, &index );
 
       /* SVGA_NEW_VELEMENT
@@ -121,8 +109,16 @@ static int emit_hw_vs_vdecl( struct svga_context *svga,
       decl.identity.usage = usage;
       decl.identity.usageIndex = index;
       decl.array.stride = vb->stride;
-      decl.array.offset = (vb->buffer_offset +
-                           ve[i].src_offset);
+
+      /* Compensate for partially uploaded vbo, and
+       * for the negative index bias.
+       */
+      decl.array.offset = (vb->buffer_offset
+                           + ve[i].src_offset
+			   + neg_bias * vb->stride
+			   - buffer->source_offset);
+
+      assert(decl.array.offset >= 0);
 
       svga_hwtnl_vdecl( svga->hwtnl,
                         i,
@@ -131,6 +127,7 @@ static int emit_hw_vs_vdecl( struct svga_context *svga,
                         vb->buffer );
    }
 
+   svga_hwtnl_set_index_bias( svga->hwtnl, -neg_bias );
    return 0;
 }
 
@@ -138,23 +135,11 @@ static int emit_hw_vs_vdecl( struct svga_context *svga,
 static int emit_hw_vdecl( struct svga_context *svga,
                           unsigned dirty )
 {
-   int ret = 0;
-
    /* SVGA_NEW_NEED_SWTNL
     */
    if (svga->state.sw.need_swtnl)
       return 0; /* Do not emit during swtnl */
 
-   /* If we get to here, we know that we're going to draw.  Upload
-    * userbuffers now and try to combine multiple userbuffers from
-    * multiple draw calls into a single host buffer for performance.
-    */
-   if (svga->curr.any_user_vertex_buffers) {
-      ret = upload_user_buffers( svga );
-      if (ret)
-         return ret;
-   }
-
    return emit_hw_vs_vdecl( svga, dirty );
 }