[Mesa-dev] [PATCH 1/4] radeonsi: fix primitive ID in fragment shader when using tessellation

[Nicolai Hähnle]

From: Nicolai Hähnle <nicolai.haehnle at amd.com>

In a VS->TCS->TES->PS pipeline, the primitive ID is read from TES exports,
so it is as if TES were using the primitive ID.

Specifically, this fixes a bug where the primitive ID is not reset at
the start of a new instance.

Cc: mesa-stable at lists.freedesktop.org
---
 src/gallium/drivers/radeonsi/si_state_shaders.c | 27 ++++++++++++++++---------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/src/gallium/drivers/radeonsi/si_state_shaders.c b/src/gallium/drivers/radeonsi/si_state_shaders.c
index e479422..d756f30 100644
--- a/src/gallium/drivers/radeonsi/si_state_shaders.c
+++ b/src/gallium/drivers/radeonsi/si_state_shaders.c
@@ -2132,50 +2132,55 @@ static void si_bind_vs_shader(struct pipe_context *ctx, void *state)
 	if (sctx->vs_shader.cso == sel)
 		return;
 
 	sctx->vs_shader.cso = sel;
 	sctx->vs_shader.current = sel ? sel->first_variant : NULL;
 	sctx->do_update_shaders = true;
 	si_mark_atom_dirty(sctx, &sctx->clip_regs);
 	r600_update_vs_writes_viewport_index(&sctx->b, si_get_vs_info(sctx));
 }
 
+static void si_update_tcs_tes_uses_prim_id(struct si_context *sctx)
+{
+	sctx->ia_multi_vgt_param_key.u.tcs_tes_uses_prim_id =
+		(sctx->tes_shader.cso &&
+		 sctx->tes_shader.cso->info.uses_primid) ||
+		(sctx->tcs_shader.cso &&
+		 sctx->tcs_shader.cso->info.uses_primid) ||
+		(sctx->ps_shader.cso && !sctx->gs_shader.cso &&
+		 sctx->ps_shader.cso->info.uses_primid);
+}
+
 static void si_bind_gs_shader(struct pipe_context *ctx, void *state)
 {
 	struct si_context *sctx = (struct si_context *)ctx;
 	struct si_shader_selector *sel = state;
 	bool enable_changed = !!sctx->gs_shader.cso != !!sel;
 
 	if (sctx->gs_shader.cso == sel)
 		return;
 
 	sctx->gs_shader.cso = sel;
 	sctx->gs_shader.current = sel ? sel->first_variant : NULL;
 	sctx->ia_multi_vgt_param_key.u.uses_gs = sel != NULL;
 	sctx->do_update_shaders = true;
 	si_mark_atom_dirty(sctx, &sctx->clip_regs);
 	sctx->last_rast_prim = -1; /* reset this so that it gets updated */
 
-	if (enable_changed)
+	if (enable_changed) {
 		si_shader_change_notify(sctx);
+		if (sctx->ia_multi_vgt_param_key.u.uses_tess)
+			si_update_tcs_tes_uses_prim_id(sctx);
+	}
 	r600_update_vs_writes_viewport_index(&sctx->b, si_get_vs_info(sctx));
 }
 
-static void si_update_tcs_tes_uses_prim_id(struct si_context *sctx)
-{
-	sctx->ia_multi_vgt_param_key.u.tcs_tes_uses_prim_id =
-		(sctx->tes_shader.cso &&
-		 sctx->tes_shader.cso->info.uses_primid) ||
-		(sctx->tcs_shader.cso &&
-		 sctx->tcs_shader.cso->info.uses_primid);
-}
-
 static void si_bind_tcs_shader(struct pipe_context *ctx, void *state)
 {
 	struct si_context *sctx = (struct si_context *)ctx;
 	struct si_shader_selector *sel = state;
 	bool enable_changed = !!sctx->tcs_shader.cso != !!sel;
 
 	if (sctx->tcs_shader.cso == sel)
 		return;
 
 	sctx->tcs_shader.cso = sel;
@@ -2216,20 +2221,22 @@ static void si_bind_ps_shader(struct pipe_context *ctx, void *state)
 	struct si_context *sctx = (struct si_context *)ctx;
 	struct si_shader_selector *sel = state;
 
 	/* skip if supplied shader is one already in use */
 	if (sctx->ps_shader.cso == sel)
 		return;
 
 	sctx->ps_shader.cso = sel;
 	sctx->ps_shader.current = sel ? sel->first_variant : NULL;
 	sctx->do_update_shaders = true;
+	if (sel && sctx->ia_multi_vgt_param_key.u.uses_tess)
+		si_update_tcs_tes_uses_prim_id(sctx);
 	si_mark_atom_dirty(sctx, &sctx->cb_render_state);
 }
 
 static void si_delete_shader(struct si_context *sctx, struct si_shader *shader)
 {
 	if (shader->is_optimized) {
 		util_queue_fence_wait(&shader->optimized_ready);
 		util_queue_fence_destroy(&shader->optimized_ready);
 	}
 
-- 
2.9.3