drm/amd/display: Allow individual control of eDP hotplug support

[Why]
Second eDP can send display off notification through HPD
but DC isn't hooked up to handle. Some primary eDP panels
will toggle on/off incorrectly if it's enabled generically.

[How]
Extend the debug option to allow individually enabling hotplug
either the first eDP or the second eDP in a dual eDP system.
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Derek Lai <Derek.Lai@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/core/dc_link.c

@@ -1605,8 +1605,25 @@ static bool dc_link_construct_legacy(struct dc_link *link,
 		if (link->hpd_gpio) {
 			if (!link->dc->config.allow_edp_hotplug_detection)
 				link->irq_source_hpd = DC_IRQ_SOURCE_INVALID;
-			link->irq_source_hpd_rx =
-					dal_irq_get_rx_source(link->hpd_gpio);
+
+			switch (link->dc->config.allow_edp_hotplug_detection) {
+			case 1: // only the 1st eDP handles hotplug
+				if (link->link_index == 0)
+					link->irq_source_hpd_rx =
+						dal_irq_get_rx_source(link->hpd_gpio);
+				else
+					link->irq_source_hpd = DC_IRQ_SOURCE_INVALID;
+				break;
+			case 2: // only the 2nd eDP handles hotplug
+				if (link->link_index == 1)
+					link->irq_source_hpd_rx =
+						dal_irq_get_rx_source(link->hpd_gpio);
+				else
+					link->irq_source_hpd = DC_IRQ_SOURCE_INVALID;
+				break;
+			default:
+				break;
+			}
 		}
 
 		break;

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

@@ -329,7 +329,7 @@ struct dc_config {
 	bool disable_dmcu;
 	bool enable_4to1MPC;
 	bool enable_windowed_mpo_odm;
-	bool allow_edp_hotplug_detection;
+	uint32_t allow_edp_hotplug_detection;
 	bool clamp_min_dcfclk;
 	uint64_t vblank_alignment_dto_params;
 	uint8_t  vblank_alignment_max_frame_time_diff;