3 files changed, 7 insertions, 8 deletions
diff --git a/src/mesa/drivers/dri/i915/i915_context.h b/src/mesa/drivers/dri/i915/i915_context.h
index 30ca25021f9..4e68d1193ca 100644
--- a/src/mesa/drivers/dri/i915/i915_context.h
+++ b/src/mesa/drivers/dri/i915/i915_context.h
@@ -117,6 +117,7 @@ enum {
 };
 
 #define I915_TEX_UNITS 8
+#define I915_WPOS_TEX_INVALID 0xff
 
 #define I915_MAX_CONSTANT      32
 #define I915_CONSTANT_SIZE     (2+(4*I915_MAX_CONSTANT))
diff --git a/src/mesa/drivers/dri/i915/i915_fragprog.c b/src/mesa/drivers/dri/i915/i915_fragprog.c
index e2d462aa374..2e043195121 100644
--- a/src/mesa/drivers/dri/i915/i915_fragprog.c
+++ b/src/mesa/drivers/dri/i915/i915_fragprog.c
@@ -1063,7 +1063,7 @@ check_wpos(struct i915_fragment_program *p)
    GLint i;
    unsigned unit = 0;
 
-   p->wpos_tex = -1;
+   p->wpos_tex = I915_WPOS_TEX_INVALID;
 
    if ((inputs & VARYING_BIT_POS) == 0)
       return;
@@ -1253,12 +1253,10 @@ i915ValidateFragmentProgram(struct i915_context *i915)
    intel->coloroffset = 0;
    intel->specoffset = 0;
 
-   if (inputsRead & VARYING_BITS_TEX_ANY || p->wpos_tex != -1) {
-      EMIT_ATTR(_TNL_ATTRIB_POS, EMIT_4F_VIEWPORT, S4_VFMT_XYZW, 16);
-   }
-   else {
-      EMIT_ATTR(_TNL_ATTRIB_POS, EMIT_3F_VIEWPORT, S4_VFMT_XYZ, 12);
-   }
+   /* Always emit W to get consistent perspective
+    * correct interpolation of primary/secondary colors.
+    */
+   EMIT_ATTR(_TNL_ATTRIB_POS, EMIT_4F_VIEWPORT, S4_VFMT_XYZW, 16);
 
    /* Handle gl_PointSize builtin var here */
    if (ctx->Point._Attenuated || ctx->VertexProgram.PointSizeEnabled)
diff --git a/src/mesa/drivers/dri/i915/i915_program.c b/src/mesa/drivers/dri/i915/i915_program.c
index a8f693f71af..20a47804249 100644
--- a/src/mesa/drivers/dri/i915/i915_program.c
+++ b/src/mesa/drivers/dri/i915/i915_program.c
@@ -482,7 +482,7 @@ i915_init_program(struct i915_context *i915, struct i915_fragment_program *p)
    p->decl_t = 0;
    p->temp_flag = 0xffff000;
    p->utemp_flag = ~0x7;
-   p->wpos_tex = -1;
+   p->wpos_tex = I915_WPOS_TEX_INVALID;
    p->depth_written = 0;
    p->nr_params = 0;