Revert "r600g: get rid of dummy pixel shader"

This reverts commit 61e47d92c5196bf0240e322bb1b9d305836559e3.

It causes a hang on RS780.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100663

3 files changed, 40 insertions, 30 deletions

diff --git a/src/gallium/drivers/r600/r600_pipe.c b/src/gallium/drivers/r600/r600_pipe.c
index 7d8efd2c9b..5014f2525c 100644
--- a/src/gallium/drivers/r600/r600_pipe.c
+++ b/src/gallium/drivers/r600/r600_pipe.c
@@ -82,6 +82,9 @@ static void r600_destroy_context(struct pipe_context *context)
 	if (rctx->fixed_func_tcs_shader)
 		rctx->b.b.delete_tcs_state(&rctx->b.b, rctx->fixed_func_tcs_shader);
 
+	if (rctx->dummy_pixel_shader) {
+		rctx->b.b.delete_fs_state(&rctx->b.b, rctx->dummy_pixel_shader);
+	}
 	if (rctx->custom_dsa_flush) {
 		rctx->b.b.delete_depth_stencil_alpha_state(&rctx->b.b, rctx->custom_dsa_flush);
 	}
@@ -206,6 +209,12 @@ static struct pipe_context *r600_create_context(struct pipe_screen *screen,
 
 	r600_begin_new_cs(rctx);
 
+	rctx->dummy_pixel_shader =
+		util_make_fragment_cloneinput_shader(&rctx->b.b, 0,
+						     TGSI_SEMANTIC_GENERIC,
+						     TGSI_INTERPOLATE_CONSTANT);
+	rctx->b.b.bind_fs_state(&rctx->b.b, rctx->dummy_pixel_shader);
+
 	return &rctx->b.b;
 
 fail:
diff --git a/src/gallium/drivers/r600/r600_pipe.h b/src/gallium/drivers/r600/r600_pipe.h
index e636ef0024..7f1ecc278b 100644
--- a/src/gallium/drivers/r600/r600_pipe.h
+++ b/src/gallium/drivers/r600/r600_pipe.h
@@ -432,6 +432,9 @@ struct r600_context {
 	void				*custom_blend_resolve;
 	void				*custom_blend_decompress;
 	void                            *custom_blend_fastclear;
+	/* With rasterizer discard, there doesn't have to be a pixel shader.
+	 * In that case, we bind this one: */
+	void				*dummy_pixel_shader;
 	/* These dummy CMASK and FMASK buffers are used to get around the R6xx hardware
 	 * bug where valid CMASK and FMASK are required to be present to avoid
 	 * a hardlock in certain operations but aren't actually used
diff --git a/src/gallium/drivers/r600/r600_state_common.c b/src/gallium/drivers/r600/r600_state_common.c
index 0131ea80d2..5be49dcdfe 100644
--- a/src/gallium/drivers/r600/r600_state_common.c
+++ b/src/gallium/drivers/r600/r600_state_common.c
@@ -725,8 +725,7 @@ static inline void r600_shader_selector_key(const struct pipe_context *ctx,
 		if (!key->vs.as_ls)
 			key->vs.as_es = (rctx->gs_shader != NULL);
 
-		if (rctx->ps_shader && rctx->ps_shader->current->shader.gs_prim_id_input &&
-		    !rctx->gs_shader) {
+		if (rctx->ps_shader->current->shader.gs_prim_id_input && !rctx->gs_shader) {
 			key->vs.as_gs_a = true;
 			key->vs.prim_id_out = rctx->ps_shader->current->shader.input[rctx->ps_shader->current->shader.ps_prim_id_input].spi_sid;
 		}
@@ -910,6 +909,9 @@ static void r600_bind_ps_state(struct pipe_context *ctx, void *state)
 {
 	struct r600_context *rctx = (struct r600_context *)ctx;
 
+	if (!state)
+		state = rctx->dummy_pixel_shader;
+
 	rctx->ps_shader = (struct r600_pipe_shader_selector *)state;
 }
 
@@ -1476,8 +1478,7 @@ static bool r600_update_derived_state(struct r600_context *rctx)
 		}
 	}
 
-	if (rctx->ps_shader)
-		SELECT_SHADER_OR_FAIL(ps);
+	SELECT_SHADER_OR_FAIL(ps);
 
 	r600_mark_atom_dirty(rctx, &rctx->shader_stages.atom);
 
@@ -1554,40 +1555,37 @@ static bool r600_update_derived_state(struct r600_context *rctx)
 		rctx->b.streamout.enabled_stream_buffers_mask = clip_so_current->enabled_stream_buffers_mask;
 	}
 
-	if (rctx->ps_shader) {
-		if (unlikely((ps_dirty || rctx->hw_shader_stages[R600_HW_STAGE_PS].shader != rctx->ps_shader->current ||
-			      rctx->rasterizer->sprite_coord_enable != rctx->ps_shader->current->sprite_coord_enable ||
-			      rctx->rasterizer->flatshade != rctx->ps_shader->current->flatshade))) {
+	if (unlikely(ps_dirty || rctx->hw_shader_stages[R600_HW_STAGE_PS].shader != rctx->ps_shader->current ||
+		rctx->rasterizer->sprite_coord_enable != rctx->ps_shader->current->sprite_coord_enable ||
+		rctx->rasterizer->flatshade != rctx->ps_shader->current->flatshade)) {
 
-			if (rctx->cb_misc_state.nr_ps_color_outputs != rctx->ps_shader->current->nr_ps_color_outputs) {
-				rctx->cb_misc_state.nr_ps_color_outputs = rctx->ps_shader->current->nr_ps_color_outputs;
-				r600_mark_atom_dirty(rctx, &rctx->cb_misc_state.atom);
-			}
+		if (rctx->cb_misc_state.nr_ps_color_outputs != rctx->ps_shader->current->nr_ps_color_outputs) {
+			rctx->cb_misc_state.nr_ps_color_outputs = rctx->ps_shader->current->nr_ps_color_outputs;
+			r600_mark_atom_dirty(rctx, &rctx->cb_misc_state.atom);
+		}
 
-			if (rctx->b.chip_class <= R700) {
-				bool multiwrite = rctx->ps_shader->current->shader.fs_write_all;
+		if (rctx->b.chip_class <= R700) {
+			bool multiwrite = rctx->ps_shader->current->shader.fs_write_all;
 
-				if (rctx->cb_misc_state.multiwrite != multiwrite) {
-					rctx->cb_misc_state.multiwrite = multiwrite;
-					r600_mark_atom_dirty(rctx, &rctx->cb_misc_state.atom);
-				}
+			if (rctx->cb_misc_state.multiwrite != multiwrite) {
+				rctx->cb_misc_state.multiwrite = multiwrite;
+				r600_mark_atom_dirty(rctx, &rctx->cb_misc_state.atom);
 			}
+		}
 
-			if (unlikely(!ps_dirty && rctx->rasterizer &&
-				     ((rctx->rasterizer->sprite_coord_enable != rctx->ps_shader->current->sprite_coord_enable) ||
-				      (rctx->rasterizer->flatshade != rctx->ps_shader->current->flatshade)))) {
-
-				if (rctx->b.chip_class >= EVERGREEN)
-					evergreen_update_ps_state(ctx, rctx->ps_shader->current);
-				else
-					r600_update_ps_state(ctx, rctx->ps_shader->current);
-			}
+		if (unlikely(!ps_dirty && rctx->ps_shader && rctx->rasterizer &&
+				((rctx->rasterizer->sprite_coord_enable != rctx->ps_shader->current->sprite_coord_enable) ||
+						(rctx->rasterizer->flatshade != rctx->ps_shader->current->flatshade)))) {
 
-			r600_mark_atom_dirty(rctx, &rctx->shader_stages.atom);
+			if (rctx->b.chip_class >= EVERGREEN)
+				evergreen_update_ps_state(ctx, rctx->ps_shader->current);
+			else
+				r600_update_ps_state(ctx, rctx->ps_shader->current);
 		}
 
-		UPDATE_SHADER(R600_HW_STAGE_PS, ps);
+		r600_mark_atom_dirty(rctx, &rctx->shader_stages.atom);
 	}
+	UPDATE_SHADER(R600_HW_STAGE_PS, ps);
 
 	if (rctx->b.chip_class >= EVERGREEN) {
 		evergreen_update_db_shader_control(rctx);
@@ -1643,7 +1641,7 @@ static bool r600_update_derived_state(struct r600_context *rctx)
 		}
 	}
 
-	blend_disable = (rctx->dual_src_blend && rctx->ps_shader &&
+	blend_disable = (rctx->dual_src_blend &&
 			rctx->ps_shader->current->nr_ps_color_outputs < 2);
 
 	if (blend_disable != rctx->force_blend_disable) {