drm/amd/display: Keep PHY active for DP displays on DCN31

[Why & How]
Port of a change that went into DCN314 to keep the PHY enabled
when we have a connected and active DP display.

The PHY can hang if PHY refclk is disabled inadvertently.

Cc: Mario Limonciello <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: [email protected]
Reviewed-by: Josip Pavic <[email protected]>
Acked-by: Alan Liu <[email protected]>
Signed-off-by: Nicholas Kazlauskas <[email protected]>
Tested-by: Daniel Wheeler <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

Author: Nicholas Kazlauskas

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn31/dcn31_clk_mgr.c

@@ -87,6 +87,11 @@ static int dcn31_get_active_display_cnt_wa(
 				stream->signal == SIGNAL_TYPE_DVI_SINGLE_LINK ||
 				stream->signal == SIGNAL_TYPE_DVI_DUAL_LINK)
 			tmds_present = true;
+
+		/* Checking stream / link detection ensuring that PHY is active*/
+		if (dc_is_dp_signal(stream->signal) && !stream->dpms_off)
+			display_count++;
+
 	}
 
 	for (i = 0; i < dc->link_count; i++) {