drm/amd/display: add debug option for z9 disable interface

[Why]
To help triage issues and coordinate driver/bios release dependency

[How]
Only enable the new Z9 interface when debug option is set, otherwise
treat Z10 only support case as Zstate disallowed.
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Eric Yang <Eric.Yang2@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn31/dcn31_smu.c

@@ -308,12 +308,16 @@ void dcn31_smu_transfer_wm_table_dram_2_smu(struct clk_mgr_internal *clk_mgr)
 
 void dcn31_smu_set_zstate_support(struct clk_mgr_internal *clk_mgr, enum dcn_zstate_support_state support)
 {
-	//TODO: Work with smu team to define optimization options.
 	unsigned int msg_id, param;
 
 	if (!clk_mgr->smu_present)
 		return;
 
+	if (!clk_mgr->base.ctx->dc->debug.enable_z9_disable_interface &&
+			(support == DCN_ZSTATE_SUPPORT_ALLOW_Z10_ONLY))
+		support = DCN_ZSTATE_SUPPORT_DISALLOW;
+
+
 	if (support == DCN_ZSTATE_SUPPORT_ALLOW_Z10_ONLY)
 		param = 1;
 	else

drivers/gpu/drm/amd/display/dc/dc.h

@@ -703,6 +703,7 @@ struct dc_debug_options {
 	int crb_alloc_policy_min_disp_count;
 #if defined(CONFIG_DRM_AMD_DC_DCN)
 	bool disable_z10;
+	bool enable_z9_disable_interface;
 	bool enable_sw_cntl_psr;
 	union dpia_debug_options dpia_debug;
 #endif

drivers/gpu/drm/amd/display/dc/dcn31/dcn31_resource.c

@@ -1033,6 +1033,7 @@ static const struct dc_debug_options debug_defaults_drv = {
 	.optimize_edp_link_rate = true,
 	.enable_sw_cntl_psr = true,
 	.apply_vendor_specific_lttpr_wa = true,
+	.enable_z9_disable_interface = false
 };
 
 static const struct dc_debug_options debug_defaults_diags = {