drm/amd/display: Add debug key to allow disabling dtbclk

[HOW]
Add debug key to allow disabling dtbclk
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Acked-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Muhammad Ahmed <ahmed.ahmed@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn35/dcn35_clk_mgr.c

@@ -244,7 +244,8 @@ void dcn35_update_clocks(struct clk_mgr *clk_mgr_base,
 		}
 
 		if (clk_mgr_base->clks.dtbclk_en && !new_clocks->dtbclk_en) {
-			dcn35_smu_set_dtbclk(clk_mgr, false);
+			if (clk_mgr->base.ctx->dc->config.allow_0_dtb_clk)
+				dcn35_smu_set_dtbclk(clk_mgr, false);
 			clk_mgr_base->clks.dtbclk_en = new_clocks->dtbclk_en;
 		}
 		/* check that we're not already in lower */

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

@@ -435,6 +435,7 @@ struct dc_config {
 	unsigned int disable_ips;
 	unsigned int disable_ips_in_vpb;
 	bool usb4_bw_alloc_support;
+	bool allow_0_dtb_clk;
 };
 
 enum visual_confirm {