drm/amd/display: limit timing for single dimm memory

[Why]
1. It could hit bandwidth limitdation under single dimm
memory when connecting 8K external monitor.
2. IsSupportedVidPn got validation failed with
2K240Hz eDP + 8K24Hz external monitor.
3. It's better to filter out such combination in
EnumVidPnCofuncModality
4. For short term, filter out in dc bandwidth validation.

[How]
Force 2K@240Hz+8K@24Hz timing validation false in dc.

Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Daniel Miess <Daniel.Miess@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

Author: Daniel Miess

drivers/gpu/drm/amd/display/dc/dcn314/dcn314_resource.c

@@ -1697,6 +1697,23 @@ static void dcn314_get_panel_config_defaults(struct dc_panel_config *panel_confi
 	*panel_config = panel_config_defaults;
 }
 
+static bool filter_modes_for_single_channel_workaround(struct dc *dc,
+		struct dc_state *context)
+{
+	// Filter 2K@240Hz+8K@24fps above combination timing if memory only has single dimm LPDDR
+	if (dc->clk_mgr->bw_params->vram_type == 34 && dc->clk_mgr->bw_params->num_channels < 2) {
+		int total_phy_pix_clk = 0;
+
+		for (int i = 0; i < context->stream_count; i++)
+			if (context->res_ctx.pipe_ctx[i].stream)
+				total_phy_pix_clk += context->res_ctx.pipe_ctx[i].stream->phy_pix_clk;
+
+		if (total_phy_pix_clk >= (1148928+826260)) //2K@240Hz+8K@24fps
+			return true;
+	}
+	return false;
+}
+
 bool dcn314_validate_bandwidth(struct dc *dc,
 		struct dc_state *context,
 		bool fast_validate)
@@ -1712,6 +1729,9 @@ bool dcn314_validate_bandwidth(struct dc *dc,
 
 	BW_VAL_TRACE_COUNT();
 
+	if (filter_modes_for_single_channel_workaround(dc, context))
+		goto validate_fail;
+
 	DC_FP_START();
 	// do not support self refresh only
 	out = dcn30_internal_validate_bw(dc, context, pipes, &pipe_cnt, &vlevel, fast_validate, false);