drm/amd/display: screen flickers when connected to ext monitor in clone

Signed-off-by: Hersen Wu <hersenxs.wu@amd.com>
Signed-off-by: Tony Cheng <tony.cheng@amd.com>
Reviewed-by: Hersen Wu <hersenxs.wu@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/calcs/dcn_calcs.c

@@ -1018,9 +1018,17 @@ bool dcn_validate_bandwidth(
 		context->bw.dcn.calc_clk.min_active_dram_ccm_us = (int)(v->min_active_dram_clock_change_margin);
 		context->bw.dcn.calc_clk.dcfclk_deep_sleep_khz = (int)(v->dcf_clk_deep_sleep * 1000);
 		context->bw.dcn.calc_clk.dcfclk_khz = (int)(v->dcfclk * 1000);
+
 		context->bw.dcn.calc_clk.dispclk_khz = (int)(v->dispclk * 1000);
 		if (dc->debug.max_disp_clk == true)
 			context->bw.dcn.calc_clk.dispclk_khz = (int)(dc->dcn_soc->max_dispclk_vmax0p9 * 1000);
+
+		if (context->bw.dcn.calc_clk.dispclk_khz <
+				dc->debug.min_disp_clk_khz) {
+			context->bw.dcn.calc_clk.dispclk_khz =
+					dc->debug.min_disp_clk_khz;
+		}
+
 		context->bw.dcn.calc_clk.dppclk_div = (int)(v->dispclk_dppclk_ratio) == 2;
 
 		for (i = 0, input_idx = 0; i < pool->pipe_count; i++) {

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

@@ -178,6 +178,7 @@ struct dc_debug {
 	bool disable_pplib_wm_range;
 	bool use_dml_wm;
 	bool disable_pipe_split;
+	unsigned int min_disp_clk_khz;
 	int sr_exit_time_dpm0_ns;
 	int sr_enter_plus_exit_time_dpm0_ns;
 	int sr_exit_time_ns;

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_resource.c

@@ -420,6 +420,9 @@ static const struct dc_debug debug_defaults_drv = {
 		.force_abm_enable = false,
 		.timing_trace = false,
 		.clock_trace = true,
+
+		.min_disp_clk_khz = 300000,
+
 		.disable_pplib_clock_request = true,
 		.disable_pplib_wm_range = false,
 #if defined(CONFIG_DRM_AMD_DC_DCN1_0)