drm/amd/display: eDP intermittent black screen during PnP

[Why]
We dont's turn off backlight before power off eDP (VDD),
which is a violation of eDP specs.

[How]
Power off eDP backlight before power off eDP
Signed-off-by: Peikang Zhang <peikang.zhang@amd.com>
Reviewed-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc_link_hwss.c

@@ -229,6 +229,8 @@ void dp_disable_link_phy(struct dc_link *link, enum signal_type signal)
 		dp_receiver_power_ctrl(link, false);
 
 	if (signal == SIGNAL_TYPE_EDP) {
+		if (link->dc->hwss.edp_backlight_control)
+			link->dc->hwss.edp_backlight_control(link, false);
 		link->link_enc->funcs->disable_output(link->link_enc, signal);
 		link->dc->hwss.edp_power_control(link, false);
 	} else {

drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c

@@ -2890,6 +2890,7 @@ static const struct hw_sequencer_funcs dce110_funcs = {
 	.setup_stereo = NULL,
 	.set_avmute = dce110_set_avmute,
 	.wait_for_mpcc_disconnect = dce110_wait_for_mpcc_disconnect,
+	.edp_backlight_control = dce110_edp_backlight_control,
 	.edp_power_control = dce110_edp_power_control,
 	.edp_wait_for_hpd_ready = dce110_edp_wait_for_hpd_ready,
 	.set_cursor_position = dce110_set_cursor_position,

drivers/gpu/drm/amd/display/dc/dcn10/dcn10_init.c

@@ -66,6 +66,7 @@ static const struct hw_sequencer_funcs dcn10_funcs = {
 	.get_hw_state = dcn10_get_hw_state,
 	.clear_status_bits = dcn10_clear_status_bits,
 	.wait_for_mpcc_disconnect = dcn10_wait_for_mpcc_disconnect,
+	.edp_backlight_control = dce110_edp_backlight_control,
 	.edp_power_control = dce110_edp_power_control,
 	.edp_wait_for_hpd_ready = dce110_edp_wait_for_hpd_ready,
 	.set_cursor_position = dcn10_set_cursor_position,

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_init.c

@@ -68,6 +68,7 @@ static const struct hw_sequencer_funcs dcn20_funcs = {
 	.get_hw_state = dcn10_get_hw_state,
 	.clear_status_bits = dcn10_clear_status_bits,
 	.wait_for_mpcc_disconnect = dcn10_wait_for_mpcc_disconnect,
+	.edp_backlight_control = dce110_edp_backlight_control,
 	.edp_power_control = dce110_edp_power_control,
 	.edp_wait_for_hpd_ready = dce110_edp_wait_for_hpd_ready,
 	.set_cursor_position = dcn10_set_cursor_position,

drivers/gpu/drm/amd/display/dc/dcn21/dcn21_init.c

@@ -69,6 +69,7 @@ static const struct hw_sequencer_funcs dcn21_funcs = {
 	.get_hw_state = dcn10_get_hw_state,
 	.clear_status_bits = dcn10_clear_status_bits,
 	.wait_for_mpcc_disconnect = dcn10_wait_for_mpcc_disconnect,
+	.edp_backlight_control = dce110_edp_backlight_control,
 	.edp_power_control = dce110_edp_power_control,
 	.edp_wait_for_hpd_ready = dce110_edp_wait_for_hpd_ready,
 	.set_cursor_position = dcn10_set_cursor_position,

drivers/gpu/drm/amd/display/dc/dcn30/dcn30_init.c

@@ -69,6 +69,7 @@ static const struct hw_sequencer_funcs dcn30_funcs = {
 	.get_hw_state = dcn10_get_hw_state,
 	.clear_status_bits = dcn10_clear_status_bits,
 	.wait_for_mpcc_disconnect = dcn10_wait_for_mpcc_disconnect,
+	.edp_backlight_control = dce110_edp_backlight_control,
 	.edp_power_control = dce110_edp_power_control,
 	.edp_wait_for_hpd_ready = dce110_edp_wait_for_hpd_ready,
 	.set_cursor_position = dcn10_set_cursor_position,