drm/amdgpu: get display info from DC when DC enabled.

Signed-off-by: Rex Zhu <Rex.Zhu@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_cgs.c

@@ -889,10 +889,6 @@ static int amdgpu_cgs_get_active_displays_info(struct cgs_device *cgs_device,
 					  struct cgs_display_info *info)
 {
 	CGS_FUNC_ADEV;
-	struct amdgpu_crtc *amdgpu_crtc;
-	struct drm_device *ddev = adev->ddev;
-	struct drm_crtc *crtc;
-	uint32_t line_time_us, vblank_lines;
 	struct cgs_mode_info *mode_info;
 
 	if (info == NULL)
@@ -906,6 +902,12 @@ static int amdgpu_cgs_get_active_displays_info(struct cgs_device *cgs_device,
 		mode_info->ref_clock = adev->clock.spll.reference_freq;
 	}
 
+	if (!amdgpu_device_has_dc_support(adev)) {
+		struct amdgpu_crtc *amdgpu_crtc;
+		struct drm_device *ddev = adev->ddev;
+		struct drm_crtc *crtc;
+		uint32_t line_time_us, vblank_lines;
+
 		if (adev->mode_info.num_crtc && adev->mode_info.mode_config_initialized) {
 			list_for_each_entry(crtc,
 					&ddev->mode_config.crtc_list, head) {
@@ -929,7 +931,14 @@ static int amdgpu_cgs_get_active_displays_info(struct cgs_device *cgs_device,
 				}
 			}
 		}
-
+	} else {
+		info->display_count = adev->pm.pm_display_cfg.num_display;
+		if (mode_info != NULL) {
+			mode_info->vblank_time_us = adev->pm.pm_display_cfg.min_vblank_time;
+			mode_info->refresh_rate = adev->pm.pm_display_cfg.vrefresh;
+			mode_info->ref_clock = adev->clock.spll.reference_freq;
+		}
+	}
 	return 0;
 }