r600g: fix lockup when hyperz & alpha test are enabled together. v3

Seems that alpha test being enabled confuse the GPU on the order in
which it should perform the Z testing. So force the order programmed
throught db shader control.

v2: Only force z order when alpha test is enabled
v3: Update db shader when binding new dsa + spelling fix

Signed-off-by: Jerome Glisse <[email protected]>
Reviewed-by: Marek Olšák <[email protected]>

1 files changed, 21 insertions, 1 deletions

diff --git a/src/gallium/drivers/r600/r600_state.c b/src/gallium/drivers/r600/r600_state.c
index 532285024f1..3f359fb0dd7 100644
--- a/src/gallium/drivers/r600/r600_state.c
+++ b/src/gallium/drivers/r600/r600_state.c
@@ -1966,6 +1966,13 @@ static void r600_emit_db_misc_state(struct r600_context *rctx, struct r600_atom
 	if (rctx->db_state.rsurf && rctx->db_state.rsurf->htile_enabled) {
 		/* FORCE_OFF means HiZ/HiS are determined by DB_SHADER_CONTROL */
 		db_render_override |= S_028D10_FORCE_HIZ_ENABLE(V_028D10_FORCE_OFF);
+		/* This is to fix a lockup when hyperz and alpha test are enabled at
+		 * the same time somehow GPU get confuse on which order to pick for
+		 * z test
+		 */
+		if (rctx->alphatest_state.sx_alpha_test_control) {
+			db_render_override |= S_028D10_FORCE_SHADER_Z_ORDER(1);
+		}
 	} else {
 		db_render_override |= S_028D10_FORCE_HIZ_ENABLE(V_028D10_FORCE_DISABLE);
 	}
@@ -2774,7 +2781,7 @@ void r600_pipe_shader_ps(struct pipe_context *ctx, struct r600_pipe_shader *shad
 				tmp);
 	}
 
-	db_shader_control = S_02880C_Z_ORDER(V_02880C_EARLY_Z_THEN_LATE_Z);
+	db_shader_control = 0;
 	for (i = 0; i < rshader->noutput; i++) {
 		if (rshader->output[i].name == TGSI_SEMANTIC_POSITION)
 			z_export = 1;
@@ -2969,6 +2976,19 @@ void r600_update_db_shader_control(struct r600_context * rctx)
 	unsigned db_shader_control = rctx->ps_shader->current->db_shader_control |
 				     S_02880C_DUAL_EXPORT_ENABLE(dual_export);
 
+	/* When alpha test is enabled we can't trust the hw to make the proper
+	 * decision on the order in which ztest should be run related to fragment
+	 * shader execution.
+	 *
+	 * If alpha test is enabled perform z test after fragment. RE_Z (early
+	 * z test but no write to the zbuffer) seems to cause lockup on r6xx/r7xx
+	 */
+	if (rctx->alphatest_state.sx_alpha_test_control) {
+		db_shader_control |= S_02880C_Z_ORDER(V_02880C_LATE_Z);
+	} else {
+		db_shader_control |= S_02880C_Z_ORDER(V_02880C_EARLY_Z_THEN_LATE_Z);
+	}
+
 	if (db_shader_control != rctx->db_misc_state.db_shader_control) {
 		rctx->db_misc_state.db_shader_control = db_shader_control;
 		rctx->db_misc_state.atom.dirty = true;