drm/amd/display: Check power_down functions exist before calling

[WHY]
The power_down() function was only defined for specific asics and will
crash the system if it is called by an asic with eDP connected that does
not have it defined.

[HOW]
Add a check for the function's existence before calling it.

Signed-off-by: Sung Lee <sung.lee@amd.com>
Reviewed-by: Yongqiang Sun <yongqiang.sun@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
index 079a33a..6086bbe 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
@@ -1378,8 +1378,11 @@ void dcn10_init_hw(struct dc *dc)
                struct dc_link *edp_link = get_edp_link(dc);
 
                if (edp_link &&
-                       edp_link->link_enc->funcs->is_dig_enabled &&
-                       edp_link->link_enc->funcs->is_dig_enabled(edp_link->link_enc)) {
+                               edp_link->link_enc->funcs->is_dig_enabled &&
+                               edp_link->link_enc->funcs->is_dig_enabled(edp_link->link_enc) &&
+                               dc->hwss.edp_backlight_control &&
+                               dc->hwss.power_down &&
+                               dc->hwss.edp_power_control) {
                        dc->hwss.edp_backlight_control(edp_link, false);
                        dc->hwss.power_down(dc);
                        dc->hwss.edp_power_control(edp_link, false);