drm/amd/display: prevent reading unitialized links

[why/how]
The function can be called on boot or after suspend when
links are not initialized, to prevent it guard it with
NULL pointer check

Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Pavle Kotarac <Pavle.Kotarac@amd.com>
Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/dc/dc_link.h b/drivers/gpu/drm/amd/display/dc/dc_link.h
index 3d4f5bf049c33e2b33adbf3d3d07d1793908bc62..4ebba641538bf13e91307c4554a3654bae8a8b09 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dc_link.h
+++ b/drivers/gpu/drm/amd/display/dc/dc_link.h
@@ -231,6 +231,8 @@ static inline void get_edp_links(const struct dc *dc,
        *edp_num = 0;
        for (i = 0; i < dc->link_count; i++) {
                // report any eDP links, even unconnected DDI's
+               if (!dc->links[i])
+                       continue;
                if (dc->links[i]->connector_signal == SIGNAL_TYPE_EDP) {
                        edp_links[*edp_num] = dc->links[i];
                        if (++(*edp_num) == MAX_NUM_EDP)