draw: nuke the interp parameter from vertex_info

draw emit couldn't care less what the interpolation mode is...
This somehow looked like it would matter, all drivers more or less
dutifully filled that in correctly. But this is only used for emit,
if draw needs to know about interpolation mode (for clipping for instance)
it will get that information from the vs anyway.
softpipe actually used to depend on that interpolation parameter, as it
abused that structure quite a bit but no longer.

Reviewed-by: Brian Paul <[email protected]>
Reviewed-by: Edward O'Callaghan <[email protected]>

11 files changed, 72 insertions, 92 deletions

diff --git a/src/gallium/auxiliary/draw/draw_vertex.h b/src/gallium/auxiliary/draw/draw_vertex.h
index ae207e2b0b3..c7b1afe5dde 100644
--- a/src/gallium/auxiliary/draw/draw_vertex.h
+++ b/src/gallium/auxiliary/draw/draw_vertex.h
@@ -62,18 +62,6 @@ enum attrib_emit {
 
 
 /**
- * Attribute interpolation mode
- */
-enum interp_mode {
-   INTERP_NONE,      /**< never interpolate vertex header info */
-   INTERP_POS,       /**< special case for frag position */
-   INTERP_CONSTANT,
-   INTERP_LINEAR,
-   INTERP_PERSPECTIVE
-};
-
-
-/**
  * Information about hardware/rasterization vertex layout.
  */
 struct vertex_info
@@ -86,8 +74,7 @@ struct vertex_info
     * memcmp() comparisons.
     */
    struct {
-      unsigned interp_mode:4;      /**< INTERP_x */
-      unsigned emit:4;             /**< EMIT_x */
+      unsigned emit:8;             /**< EMIT_x */
       unsigned src_index:8;          /**< map to post-xform attribs */
    } attrib[PIPE_MAX_SHADER_OUTPUTS];
 };
@@ -125,7 +112,6 @@ draw_vinfo_copy( struct vertex_info *dst,
 static inline uint
 draw_emit_vertex_attr(struct vertex_info *vinfo,
                       enum attrib_emit emit, 
-                      enum interp_mode interp, /* only used by softpipe??? */
                       int src_index)
 {
    const uint n = vinfo->num_attribs;
@@ -138,7 +124,6 @@ draw_emit_vertex_attr(struct vertex_info *vinfo,
 
    assert(n < Elements(vinfo->attrib));
    vinfo->attrib[n].emit = emit;
-   vinfo->attrib[n].interp_mode = interp;
    vinfo->attrib[n].src_index = src_index;
    vinfo->num_attribs++;
    return n;
diff --git a/src/gallium/drivers/i915/i915_context.h b/src/gallium/drivers/i915/i915_context.h
index 1ed685188db..2adaee30fb9 100644
--- a/src/gallium/drivers/i915/i915_context.h
+++ b/src/gallium/drivers/i915/i915_context.h
@@ -195,7 +195,6 @@ struct i915_rasterizer_state {
 
    unsigned light_twoside : 1;
    unsigned st;
-   enum interp_mode color_interp;
 
    unsigned LIS4;
    unsigned LIS7;
diff --git a/src/gallium/drivers/i915/i915_state.c b/src/gallium/drivers/i915/i915_state.c
index d1661fed3f7..b54a9fbf4f9 100644
--- a/src/gallium/drivers/i915/i915_state.c
+++ b/src/gallium/drivers/i915/i915_state.c
@@ -920,7 +920,6 @@ i915_create_rasterizer_state(struct pipe_context *pipe,
    struct i915_rasterizer_state *cso = CALLOC_STRUCT( i915_rasterizer_state );
 
    cso->templ = *rasterizer;
-   cso->color_interp = rasterizer->flatshade ? INTERP_CONSTANT : INTERP_LINEAR;
    cso->light_twoside = rasterizer->light_twoside;
    cso->ds[0].u = _3DSTATE_DEPTH_OFFSET_SCALE;
    cso->ds[1].f = rasterizer->offset_scale;
diff --git a/src/gallium/drivers/i915/i915_state_derived.c b/src/gallium/drivers/i915/i915_state_derived.c
index 7ad88a1ce01..bd0f448f645 100644
--- a/src/gallium/drivers/i915/i915_state_derived.c
+++ b/src/gallium/drivers/i915/i915_state_derived.c
@@ -57,7 +57,6 @@ static uint find_mapping(const struct i915_fragment_shader* fs, int unit)
 static void calculate_vertex_layout(struct i915_context *i915)
 {
    const struct i915_fragment_shader *fs = i915->fs;
-   const enum interp_mode colorInterp = i915->rasterizer->color_interp;
    struct vertex_info vinfo;
    boolean texCoords[I915_TEX_UNITS], colors[2], fog, needW, face;
    uint i;
@@ -107,12 +106,12 @@ static void calculate_vertex_layout(struct i915_context *i915)
    /* pos */
    src = draw_find_shader_output(i915->draw, TGSI_SEMANTIC_POSITION, 0);
    if (needW) {
-      draw_emit_vertex_attr(&vinfo, EMIT_4F, INTERP_LINEAR, src);
+      draw_emit_vertex_attr(&vinfo, EMIT_4F, src);
       vinfo.hwfmt[0] |= S4_VFMT_XYZW;
       vinfo.attrib[0].emit = EMIT_4F;
    }
    else {
-      draw_emit_vertex_attr(&vinfo, EMIT_3F, INTERP_LINEAR, src);
+      draw_emit_vertex_attr(&vinfo, EMIT_3F, src);
       vinfo.hwfmt[0] |= S4_VFMT_XYZ;
       vinfo.attrib[0].emit = EMIT_3F;
    }
@@ -123,21 +122,21 @@ static void calculate_vertex_layout(struct i915_context *i915)
    /* primary color */
    if (colors[0]) {
       src = draw_find_shader_output(i915->draw, TGSI_SEMANTIC_COLOR, 0);
-      draw_emit_vertex_attr(&vinfo, EMIT_4UB_BGRA, colorInterp, src);
+      draw_emit_vertex_attr(&vinfo, EMIT_4UB_BGRA, src);
       vinfo.hwfmt[0] |= S4_VFMT_COLOR;
    }
 
    /* secondary color */
    if (colors[1]) {
       src = draw_find_shader_output(i915->draw, TGSI_SEMANTIC_COLOR, 1);
-      draw_emit_vertex_attr(&vinfo, EMIT_4UB_BGRA, colorInterp, src);
+      draw_emit_vertex_attr(&vinfo, EMIT_4UB_BGRA, src);
       vinfo.hwfmt[0] |= S4_VFMT_SPEC_FOG;
    }
 
    /* fog coord, not fog blend factor */
    if (fog) {
       src = draw_find_shader_output(i915->draw, TGSI_SEMANTIC_FOG, 0);
-      draw_emit_vertex_attr(&vinfo, EMIT_1F, INTERP_PERSPECTIVE, src);
+      draw_emit_vertex_attr(&vinfo, EMIT_1F, src);
       vinfo.hwfmt[0] |= S4_VFMT_FOG_PARAM;
    }
 
@@ -147,7 +146,7 @@ static void calculate_vertex_layout(struct i915_context *i915)
       if (texCoords[i]) {
          hwtc = TEXCOORDFMT_4D;
          src = draw_find_shader_output(i915->draw, TGSI_SEMANTIC_GENERIC, fs->generic_mapping[i]);
-         draw_emit_vertex_attr(&vinfo, EMIT_4F, INTERP_PERSPECTIVE, src);
+         draw_emit_vertex_attr(&vinfo, EMIT_4F, src);
       }
       else {
          hwtc = TEXCOORDFMT_NOT_PRESENT;
@@ -164,7 +163,7 @@ static void calculate_vertex_layout(struct i915_context *i915)
        * module by adding an extra shader output.
        */
       src = draw_find_shader_output(i915->draw, TGSI_SEMANTIC_FACE, 0);
-      draw_emit_vertex_attr(&vinfo, EMIT_1F, INTERP_CONSTANT, src);
+      draw_emit_vertex_attr(&vinfo, EMIT_1F, src);
       vinfo.hwfmt[1] &= ~(TEXCOORDFMT_NOT_PRESENT << (slot * 4));
       vinfo.hwfmt[1] |= TEXCOORDFMT_1D << (slot * 4);
    }
@@ -185,7 +184,7 @@ static void calculate_vertex_layout(struct i915_context *i915)
 struct i915_tracked_state i915_update_vertex_layout = {
    "vertex_layout",
    calculate_vertex_layout,
-   I915_NEW_RASTERIZER | I915_NEW_FS | I915_NEW_VS
+   I915_NEW_FS | I915_NEW_VS
 };
 
 
diff --git a/src/gallium/drivers/llvmpipe/lp_state_derived.c b/src/gallium/drivers/llvmpipe/lp_state_derived.c
index f1f51cf0381..fbc2e185343 100644
--- a/src/gallium/drivers/llvmpipe/lp_state_derived.c
+++ b/src/gallium/drivers/llvmpipe/lp_state_derived.c
@@ -76,7 +76,7 @@ compute_vertex_info(struct llvmpipe_context *llvmpipe)
                                       TGSI_SEMANTIC_POSITION,
                                       0);
 
-   draw_emit_vertex_attr(vinfo, EMIT_4F, INTERP_PERSPECTIVE, vs_index);
+   draw_emit_vertex_attr(vinfo, EMIT_4F, vs_index);
 
    for (i = 0; i < lpfs->info.base.num_inputs; i++) {
       /*
@@ -95,9 +95,9 @@ compute_vertex_info(struct llvmpipe_context *llvmpipe)
 
       if (lpfs->info.base.input_semantic_name[i] == TGSI_SEMANTIC_FACE) {
          llvmpipe->face_slot = vinfo->num_attribs;
-         draw_emit_vertex_attr(vinfo, EMIT_4F, INTERP_CONSTANT, vs_index);
+         draw_emit_vertex_attr(vinfo, EMIT_4F, vs_index);
       } else if (lpfs->info.base.input_semantic_name[i] == TGSI_SEMANTIC_PRIMID) {
-         draw_emit_vertex_attr(vinfo, EMIT_4F, INTERP_CONSTANT, vs_index);
+         draw_emit_vertex_attr(vinfo, EMIT_4F, vs_index);
       /*
        * For vp index and layer, if the fs requires them but the vs doesn't
        * provide them, draw (vbuf) will give us the required 0 (slot -1).
@@ -107,15 +107,15 @@ compute_vertex_info(struct llvmpipe_context *llvmpipe)
       } else if (lpfs->info.base.input_semantic_name[i] ==
                  TGSI_SEMANTIC_VIEWPORT_INDEX) {
          llvmpipe->viewport_index_slot = vinfo->num_attribs;
-         draw_emit_vertex_attr(vinfo, EMIT_4F, INTERP_CONSTANT, vs_index);
+         draw_emit_vertex_attr(vinfo, EMIT_4F, vs_index);
       } else if (lpfs->info.base.input_semantic_name[i] == TGSI_SEMANTIC_LAYER) {
          llvmpipe->layer_slot = vinfo->num_attribs;
-         draw_emit_vertex_attr(vinfo, EMIT_4F, INTERP_CONSTANT, vs_index);
+         draw_emit_vertex_attr(vinfo, EMIT_4F, vs_index);
       } else {
          /*
           * Emit the requested fs attribute for all but position.
           */
-         draw_emit_vertex_attr(vinfo, EMIT_4F, INTERP_PERSPECTIVE, vs_index);
+         draw_emit_vertex_attr(vinfo, EMIT_4F, vs_index);
       }
    }
 
@@ -127,7 +127,7 @@ compute_vertex_info(struct llvmpipe_context *llvmpipe)
 
       if (vs_index >= 0) {
          llvmpipe->bcolor_slot[i] = vinfo->num_attribs;
-         draw_emit_vertex_attr(vinfo, EMIT_4F, INTERP_PERSPECTIVE, vs_index);
+         draw_emit_vertex_attr(vinfo, EMIT_4F, vs_index);
       }
    }
 
@@ -138,7 +138,7 @@ compute_vertex_info(struct llvmpipe_context *llvmpipe)
 
    if (vs_index >= 0) {
       llvmpipe->psize_slot = vinfo->num_attribs;
-      draw_emit_vertex_attr(vinfo, EMIT_4F, INTERP_CONSTANT, vs_index);
+      draw_emit_vertex_attr(vinfo, EMIT_4F, vs_index);
    }
 
    /* Figure out if we need viewport index (if it wasn't already in fs input) */
@@ -148,7 +148,7 @@ compute_vertex_info(struct llvmpipe_context *llvmpipe)
                                          0);
       if (vs_index >= 0) {
          llvmpipe->viewport_index_slot = vinfo->num_attribs;
-         draw_emit_vertex_attr(vinfo, EMIT_4F, INTERP_CONSTANT, vs_index);
+         draw_emit_vertex_attr(vinfo, EMIT_4F, vs_index);
       }
    }
 
@@ -159,7 +159,7 @@ compute_vertex_info(struct llvmpipe_context *llvmpipe)
                                          0);
       if (vs_index >= 0) {
          llvmpipe->layer_slot = vinfo->num_attribs;
-         draw_emit_vertex_attr(vinfo, EMIT_4F, INTERP_CONSTANT, vs_index);
+         draw_emit_vertex_attr(vinfo, EMIT_4F, vs_index);
       }
    }
 
@@ -186,10 +186,9 @@ void llvmpipe_update_derived( struct llvmpipe_context *llvmpipe )
       llvmpipe->dirty |= LP_NEW_SAMPLER_VIEW;
    }
       
-   if (llvmpipe->dirty & (LP_NEW_RASTERIZER |
-                          LP_NEW_FS |
+   if (llvmpipe->dirty & (LP_NEW_FS |
                           LP_NEW_VS))
-      compute_vertex_info( llvmpipe );
+      compute_vertex_info(llvmpipe);
 
    if (llvmpipe->dirty & (LP_NEW_FS |
                           LP_NEW_FRAMEBUFFER |
diff --git a/src/gallium/drivers/nouveau/nv30/nv30_draw.c b/src/gallium/drivers/nouveau/nv30/nv30_draw.c
index 098d6e499fa..7b0d0745766 100644
--- a/src/gallium/drivers/nouveau/nv30/nv30_draw.c
+++ b/src/gallium/drivers/nouveau/nv30/nv30_draw.c
@@ -208,17 +208,16 @@ nv30_render_release_vertices(struct vbuf_render *render)
 
 static const struct {
    unsigned emit;
-   unsigned interp;
    unsigned vp30;
    unsigned vp40;
    unsigned ow40;
 } vroute [] = {
-   [TGSI_SEMANTIC_POSITION] = { EMIT_4F, INTERP_PERSPECTIVE, 0, 0, 0x00000000 },
-   [TGSI_SEMANTIC_COLOR   ] = { EMIT_4F, INTERP_LINEAR     , 3, 1, 0x00000001 },
-   [TGSI_SEMANTIC_BCOLOR  ] = { EMIT_4F, INTERP_LINEAR     , 1, 3, 0x00000004 },
-   [TGSI_SEMANTIC_FOG     ] = { EMIT_4F, INTERP_PERSPECTIVE, 5, 5, 0x00000010 },
-   [TGSI_SEMANTIC_PSIZE   ] = { EMIT_1F_PSIZE, INTERP_POS  , 6, 6, 0x00000020 },
-   [TGSI_SEMANTIC_TEXCOORD] = { EMIT_4F, INTERP_PERSPECTIVE, 8, 7, 0x00004000 },
+   [TGSI_SEMANTIC_POSITION] = { EMIT_4F, 0, 0, 0x00000000 },
+   [TGSI_SEMANTIC_COLOR   ] = { EMIT_4F, 3, 1, 0x00000001 },
+   [TGSI_SEMANTIC_BCOLOR  ] = { EMIT_4F, 1, 3, 0x00000004 },
+   [TGSI_SEMANTIC_FOG     ] = { EMIT_4F, 5, 5, 0x00000010 },
+   [TGSI_SEMANTIC_PSIZE   ] = { EMIT_1F_PSIZE, 6, 6, 0x00000020 },
+   [TGSI_SEMANTIC_TEXCOORD] = { EMIT_4F, 8, 7, 0x00004000 },
 };
 
 static bool
@@ -247,7 +246,7 @@ vroute_add(struct nv30_render *r, uint attrib, uint sem, uint *idx)
    if (emit == EMIT_OMIT)
       return false;
 
-   draw_emit_vertex_attr(vinfo, emit, vroute[sem].interp, attrib);
+   draw_emit_vertex_attr(vinfo, emit, attrib);
    format = draw_translate_vinfo_format(emit);
 
    r->vtxfmt[attrib] = nv30_vtxfmt(&screen->base.base, format)->hw;
diff --git a/src/gallium/drivers/r300/r300_state_derived.c b/src/gallium/drivers/r300/r300_state_derived.c
index da472f4d7f4..741e263e7ed 100644
--- a/src/gallium/drivers/r300/r300_state_derived.c
+++ b/src/gallium/drivers/r300/r300_state_derived.c
@@ -52,7 +52,6 @@ enum r300_rs_col_write_type {
 
 static void r300_draw_emit_attrib(struct r300_context* r300,
                                   enum attrib_emit emit,
-                                  enum interp_mode interp,
                                   int index)
 {
     struct r300_vertex_shader* vs = r300->vs_state.state;
@@ -62,7 +61,7 @@ static void r300_draw_emit_attrib(struct r300_context* r300,
     output = draw_find_shader_output(r300->draw,
                                      info->output_semantic_name[index],
                                      info->output_semantic_index[index]);
-    draw_emit_vertex_attr(&r300->vertex_info, emit, interp, output);
+    draw_emit_vertex_attr(&r300->vertex_info, emit, output);
 }
 
 static void r300_draw_emit_all_attribs(struct r300_context* r300)
@@ -73,31 +72,27 @@ static void r300_draw_emit_all_attribs(struct r300_context* r300)
 
     /* Position. */
     if (vs_outputs->pos != ATTR_UNUSED) {
-        r300_draw_emit_attrib(r300, EMIT_4F, INTERP_PERSPECTIVE,
-                              vs_outputs->pos);
+        r300_draw_emit_attrib(r300, EMIT_4F, vs_outputs->pos);
     } else {
         assert(0);
     }
 
     /* Point size. */
     if (vs_outputs->psize != ATTR_UNUSED) {
-        r300_draw_emit_attrib(r300, EMIT_1F_PSIZE, INTERP_POS,
-                              vs_outputs->psize);
+        r300_draw_emit_attrib(r300, EMIT_1F_PSIZE, vs_outputs->psize);
     }
 
     /* Colors. */
     for (i = 0; i < ATTR_COLOR_COUNT; i++) {
         if (vs_outputs->color[i] != ATTR_UNUSED) {
-            r300_draw_emit_attrib(r300, EMIT_4F, INTERP_LINEAR,
-                                  vs_outputs->color[i]);
+            r300_draw_emit_attrib(r300, EMIT_4F, vs_outputs->color[i]);
         }
     }
 
     /* Back-face colors. */
     for (i = 0; i < ATTR_COLOR_COUNT; i++) {
         if (vs_outputs->bcolor[i] != ATTR_UNUSED) {
-            r300_draw_emit_attrib(r300, EMIT_4F, INTERP_LINEAR,
-                                  vs_outputs->bcolor[i]);
+            r300_draw_emit_attrib(r300, EMIT_4F, vs_outputs->bcolor[i]);
         }
     }
 
@@ -108,16 +103,14 @@ static void r300_draw_emit_all_attribs(struct r300_context* r300)
     for (i = 0; i < ATTR_GENERIC_COUNT && gen_count < 8; i++) {
         if (vs_outputs->generic[i] != ATTR_UNUSED &&
             !(r300->sprite_coord_enable & (1 << i))) {
-            r300_draw_emit_attrib(r300, EMIT_4F, INTERP_PERSPECTIVE,
-                                  vs_outputs->generic[i]);
+            r300_draw_emit_attrib(r300, EMIT_4F, vs_outputs->generic[i]);
             gen_count++;
         }
     }
 
     /* Fog coordinates. */
     if (gen_count < 8 && vs_outputs->fog != ATTR_UNUSED) {
-        r300_draw_emit_attrib(r300, EMIT_4F, INTERP_PERSPECTIVE,
-                              vs_outputs->fog);
+        r300_draw_emit_attrib(r300, EMIT_4F, vs_outputs->fog);
         gen_count++;
     }
 
@@ -125,8 +118,7 @@ static void r300_draw_emit_all_attribs(struct r300_context* r300)
     if (r300_fs(r300)->shader->inputs.wpos != ATTR_UNUSED && gen_count < 8) {
         DBG(r300, DBG_SWTCL, "draw_emit_attrib: WPOS, index: %i\n",
             vs_outputs->wpos);
-        r300_draw_emit_attrib(r300, EMIT_4F, INTERP_PERSPECTIVE,
-                              vs_outputs->wpos);
+        r300_draw_emit_attrib(r300, EMIT_4F, vs_outputs->wpos);
     }
 }
 
diff --git a/src/gallium/drivers/softpipe/sp_setup.c b/src/gallium/drivers/softpipe/sp_setup.c
index 28f163b4d8f..ffe49260b9a 100644
--- a/src/gallium/drivers/softpipe/sp_setup.c
+++ b/src/gallium/drivers/softpipe/sp_setup.c
@@ -38,7 +38,6 @@
 #include "sp_setup.h"
 #include "sp_state.h"
 #include "draw/draw_context.h"
-#include "draw/draw_vertex.h"
 #include "pipe/p_shader_tokens.h"
 #include "util/u_math.h"
 #include "util/u_memory.h"
@@ -624,12 +623,12 @@ setup_tri_coefficients(struct setup_context *setup)
       uint j;
 
       switch (sinfo->attrib[fragSlot].interp) {
-      case INTERP_CONSTANT:
+      case SP_INTERP_CONSTANT:
          for (j = 0; j < TGSI_NUM_CHANNELS; j++) {
             const_coeff(setup, &setup->coef[fragSlot], vertSlot, j);
          }
          break;
-      case INTERP_LINEAR:
+      case SP_INTERP_LINEAR:
          for (j = 0; j < TGSI_NUM_CHANNELS; j++) {
             tri_apply_cylindrical_wrap(setup->vmin[vertSlot][j],
                                        setup->vmid[vertSlot][j],
@@ -639,7 +638,7 @@ setup_tri_coefficients(struct setup_context *setup)
             tri_linear_coeff(setup, &setup->coef[fragSlot], j, v);
          }
          break;
-      case INTERP_PERSPECTIVE:
+      case SP_INTERP_PERSPECTIVE:
          for (j = 0; j < TGSI_NUM_CHANNELS; j++) {
             tri_apply_cylindrical_wrap(setup->vmin[vertSlot][j],
                                        setup->vmid[vertSlot][j],
@@ -649,7 +648,7 @@ setup_tri_coefficients(struct setup_context *setup)
             tri_persp_coeff(setup, &setup->coef[fragSlot], j, v);
          }
          break;
-      case INTERP_POS:
+      case SP_INTERP_POS:
          setup_fragcoord_coeff(setup, fragSlot);
          break;
       default:
@@ -1010,11 +1009,11 @@ setup_line_coefficients(struct setup_context *setup,
       uint j;
 
       switch (sinfo->attrib[fragSlot].interp) {
-      case INTERP_CONSTANT:
+      case SP_INTERP_CONSTANT:
          for (j = 0; j < TGSI_NUM_CHANNELS; j++)
             const_coeff(setup, &setup->coef[fragSlot], vertSlot, j);
          break;
-      case INTERP_LINEAR:
+      case SP_INTERP_LINEAR:
          for (j = 0; j < TGSI_NUM_CHANNELS; j++) {
             line_apply_cylindrical_wrap(setup->vmin[vertSlot][j],
                                         setup->vmax[vertSlot][j],
@@ -1023,7 +1022,7 @@ setup_line_coefficients(struct setup_context *setup,
             line_linear_coeff(setup, &setup->coef[fragSlot], j, v);
          }
          break;
-      case INTERP_PERSPECTIVE:
+      case SP_INTERP_PERSPECTIVE:
          for (j = 0; j < TGSI_NUM_CHANNELS; j++) {
             line_apply_cylindrical_wrap(setup->vmin[vertSlot][j],
                                         setup->vmax[vertSlot][j],
@@ -1032,7 +1031,7 @@ setup_line_coefficients(struct setup_context *setup,
             line_persp_coeff(setup, &setup->coef[fragSlot], j, v);
          }
          break;
-      case INTERP_POS:
+      case SP_INTERP_POS:
          setup_fragcoord_coeff(setup, fragSlot);
          break;
       default:
@@ -1296,18 +1295,18 @@ sp_setup_point(struct setup_context *setup,
       uint j;
 
       switch (sinfo->attrib[fragSlot].interp) {
-      case INTERP_CONSTANT:
+      case SP_INTERP_CONSTANT:
          /* fall-through */
-      case INTERP_LINEAR:
+      case SP_INTERP_LINEAR:
          for (j = 0; j < TGSI_NUM_CHANNELS; j++)
             const_coeff(setup, &setup->coef[fragSlot], vertSlot, j);
          break;
-      case INTERP_PERSPECTIVE:
+      case SP_INTERP_PERSPECTIVE:
          for (j = 0; j < TGSI_NUM_CHANNELS; j++)
             point_persp_coeff(setup, setup->vprovoke,
                               &setup->coef[fragSlot], vertSlot, j);
          break;
-      case INTERP_POS:
+      case SP_INTERP_POS:
          setup_fragcoord_coeff(setup, fragSlot);
          break;
       default:
diff --git a/src/gallium/drivers/softpipe/sp_setup.h b/src/gallium/drivers/softpipe/sp_setup.h
index 8bb50b98fec..9efae1cb5ed 100644
--- a/src/gallium/drivers/softpipe/sp_setup.h
+++ b/src/gallium/drivers/softpipe/sp_setup.h
@@ -30,10 +30,21 @@
 struct setup_context;
 struct softpipe_context;
 
+/**
+ * Attribute interpolation mode
+ */
+enum sp_interp_mode {
+   SP_INTERP_POS,       /**< special case for frag position */
+   SP_INTERP_CONSTANT,
+   SP_INTERP_LINEAR,
+   SP_INTERP_PERSPECTIVE
+};
+
+
 struct sp_setup_info {
    unsigned valid;
    struct {
-      unsigned interp:8;      /**< INTERP_X */
+      unsigned interp:8;      /**< SP_INTERP_X */
       unsigned src_index:8;
    } attrib[PIPE_MAX_SHADER_OUTPUTS];
 };
diff --git a/src/gallium/drivers/softpipe/sp_state_derived.c b/src/gallium/drivers/softpipe/sp_state_derived.c
index 3fb1daee2c1..ca29d76f8c2 100644
--- a/src/gallium/drivers/softpipe/sp_state_derived.c
+++ b/src/gallium/drivers/softpipe/sp_state_derived.c
@@ -78,7 +78,7 @@ softpipe_compute_vertex_info(struct softpipe_context *softpipe)
        */
       vinfo_vbuf->num_attribs = 0;
       for (i = 0; i < num; i++) {
-         draw_emit_vertex_attr(vinfo_vbuf, EMIT_4F, INTERP_PERSPECTIVE, i);
+         draw_emit_vertex_attr(vinfo_vbuf, EMIT_4F, i);
       }
       draw_compute_vertex_size(vinfo_vbuf);
 
@@ -92,17 +92,17 @@ softpipe_compute_vertex_info(struct softpipe_context *softpipe)
        */
       for (i = 0; i < fsInfo->num_inputs; i++) {
          int src;
-         enum interp_mode interp = INTERP_LINEAR;
+         enum sp_interp_mode interp = SP_INTERP_LINEAR;
 
          switch (fsInfo->input_interpolate[i]) {
          case TGSI_INTERPOLATE_CONSTANT:
-            interp = INTERP_CONSTANT;
+            interp = SP_INTERP_CONSTANT;
             break;
          case TGSI_INTERPOLATE_LINEAR:
-            interp = INTERP_LINEAR;
+            interp = SP_INTERP_LINEAR;
             break;
          case TGSI_INTERPOLATE_PERSPECTIVE:
-            interp = INTERP_PERSPECTIVE;
+            interp = SP_INTERP_PERSPECTIVE;
             break;
          case TGSI_INTERPOLATE_COLOR:
             assert(fsInfo->input_semantic_name[i] == TGSI_SEMANTIC_COLOR);
@@ -113,15 +113,15 @@ softpipe_compute_vertex_info(struct softpipe_context *softpipe)
 
          switch (fsInfo->input_semantic_name[i]) {
          case TGSI_SEMANTIC_POSITION:
-            interp = INTERP_POS;
+            interp = SP_INTERP_POS;
             break;
 
          case TGSI_SEMANTIC_COLOR:
             if (fsInfo->input_interpolate[i] == TGSI_INTERPOLATE_COLOR) {
                if (softpipe->rasterizer->flatshade)
-                  interp = INTERP_CONSTANT;
+                  interp = SP_INTERP_CONSTANT;
                else
-                  interp = INTERP_PERSPECTIVE;
+                  interp = SP_INTERP_PERSPECTIVE;
             }
             break;
          }
diff --git a/src/gallium/drivers/svga/svga_swtnl_state.c b/src/gallium/drivers/svga/svga_swtnl_state.c
index 79dc0bf580c..4d21f4f0e60 100644
--- a/src/gallium/drivers/svga/svga_swtnl_state.c
+++ b/src/gallium/drivers/svga/svga_swtnl_state.c
@@ -220,8 +220,6 @@ svga_swtnl_update_vdecl( struct svga_context *svga )
    struct draw_context *draw = svga->swtnl.draw;
    struct vertex_info *vinfo = &svga_render->vertex_info;
    SVGA3dVertexDecl vdecl[PIPE_MAX_ATTRIBS];
-   const enum interp_mode colorInterp =
-      svga->curr.rast->templ.flatshade ? INTERP_CONSTANT : INTERP_LINEAR;
    struct svga_fragment_shader *fs = svga->curr.fs;
    int offset = 0;
    int nr_decls = 0;
@@ -236,7 +234,7 @@ svga_swtnl_update_vdecl( struct svga_context *svga )
 
    /* always add position */
    src = draw_find_shader_output(draw, TGSI_SEMANTIC_POSITION, 0);
-   draw_emit_vertex_attr(vinfo, EMIT_4F, INTERP_LINEAR, src);
+   draw_emit_vertex_attr(vinfo, EMIT_4F, src);
    vinfo->attrib[0].emit = EMIT_4F;
    vdecl[0].array.offset = offset;
    vdecl[0].identity.method = SVGA3D_DECLMETHOD_DEFAULT;
@@ -257,14 +255,14 @@ svga_swtnl_update_vdecl( struct svga_context *svga )
 
       switch (sem_name) {
       case TGSI_SEMANTIC_COLOR:
-         draw_emit_vertex_attr(vinfo, EMIT_4F, colorInterp, src);
+         draw_emit_vertex_attr(vinfo, EMIT_4F, src);
          vdecl[nr_decls].identity.usage = SVGA3D_DECLUSAGE_COLOR;
          vdecl[nr_decls].identity.type = SVGA3D_DECLTYPE_FLOAT4;
          offset += 16;
          nr_decls++;
          break;
       case TGSI_SEMANTIC_GENERIC:
-         draw_emit_vertex_attr(vinfo, EMIT_4F, INTERP_PERSPECTIVE, src);
+         draw_emit_vertex_attr(vinfo, EMIT_4F, src);
          vdecl[nr_decls].identity.usage = SVGA3D_DECLUSAGE_TEXCOORD;
          vdecl[nr_decls].identity.type = SVGA3D_DECLTYPE_FLOAT4;
          vdecl[nr_decls].identity.usageIndex =
@@ -273,7 +271,7 @@ svga_swtnl_update_vdecl( struct svga_context *svga )
          nr_decls++;
          break;
       case TGSI_SEMANTIC_FOG:
-         draw_emit_vertex_attr(vinfo, EMIT_1F, INTERP_PERSPECTIVE, src);
+         draw_emit_vertex_attr(vinfo, EMIT_1F, src);
          vdecl[nr_decls].identity.usage = SVGA3D_DECLUSAGE_TEXCOORD;
          vdecl[nr_decls].identity.type = SVGA3D_DECLTYPE_FLOAT1;
          assert(vdecl[nr_decls].identity.usageIndex == 0);