r600g: emit the border color only when it's needed

That depends on the texture wrap modes and filtering.

src/gallium/drivers/r600/evergreen_state.c

@@ -939,8 +939,7 @@ static void *evergreen_create_sampler_state(struct pipe_context *ctx,
 		return NULL;
 	}
 
-	ss->border_color_use = state->border_color.ui[0] || state->border_color.ui[1] ||
-			       state->border_color.ui[2] || state->border_color.ui[3];
+	ss->border_color_use = sampler_state_needs_border_color(state);
 
 	/* R_03C000_SQ_TEX_SAMPLER_WORD0_0 */
 	ss->tex_sampler_words[0] =

src/gallium/drivers/r600/r600_pipe.h

@@ -643,6 +643,7 @@ unsigned r600_tex_wrap(unsigned wrap);
 unsigned r600_tex_filter(unsigned filter);
 unsigned r600_tex_mipfilter(unsigned filter);
 unsigned r600_tex_compare(unsigned compare);
+bool sampler_state_needs_border_color(const struct pipe_sampler_state *state);
 
 /*
  * Helpers for building command buffers

src/gallium/drivers/r600/r600_state.c

@@ -948,8 +948,7 @@ static void *r600_create_sampler_state(struct pipe_context *ctx,
 	}
 
 	ss->seamless_cube_map = state->seamless_cube_map;
-	ss->border_color_use = state->border_color.ui[0] || state->border_color.ui[1] ||
-			       state->border_color.ui[2] || state->border_color.ui[3];
+	ss->border_color_use = sampler_state_needs_border_color(state);
 
 	/* R_03C000_SQ_TEX_SAMPLER_WORD0_0 */
 	ss->tex_sampler_words[0] =

src/gallium/drivers/r600/r600_state_common.c

@@ -1523,6 +1523,27 @@ unsigned r600_tex_compare(unsigned compare)
 	}
 }
 
+static bool wrap_mode_uses_border_color(unsigned wrap, bool linear_filter)
+{
+	return wrap == PIPE_TEX_WRAP_CLAMP_TO_BORDER ||
+	       wrap == PIPE_TEX_WRAP_MIRROR_CLAMP_TO_BORDER ||
+	       (linear_filter &&
+	        (wrap == PIPE_TEX_WRAP_CLAMP ||
+		 wrap == PIPE_TEX_WRAP_MIRROR_CLAMP));
+}
+
+bool sampler_state_needs_border_color(const struct pipe_sampler_state *state)
+{
+	bool linear_filter = state->min_img_filter != PIPE_TEX_FILTER_NEAREST ||
+			     state->mag_img_filter != PIPE_TEX_FILTER_NEAREST;
+
+	return (state->border_color.ui[0] || state->border_color.ui[1] ||
+		state->border_color.ui[2] || state->border_color.ui[3]) &&
+	       (wrap_mode_uses_border_color(state->wrap_s, linear_filter) ||
+		wrap_mode_uses_border_color(state->wrap_t, linear_filter) ||
+		wrap_mode_uses_border_color(state->wrap_r, linear_filter));
+}
+
 /* keep this at the end of this file, please */
 void r600_init_common_state_functions(struct r600_context *rctx)
 {