drm/radeon/pm: don't walk the crtc list before it has been initialized (v2)

Avoids a crash in certain cases when thermal irqs are generated
before the display structures have been initialized.

v2: fix the vblank and vrefresh helpers as well

bug:
https://bugzilla.kernel.org/show_bug.cgi?id=73931

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/gpu/drm/radeon/radeon_pm.c b/drivers/gpu/drm/radeon/radeon_pm.c
index d79895a..6fac8ef 100644
--- a/drivers/gpu/drm/radeon/radeon_pm.c
+++ b/drivers/gpu/drm/radeon/radeon_pm.c
@@ -1406,12 +1406,14 @@
 
 	rdev->pm.active_crtcs = 0;
 	rdev->pm.active_crtc_count = 0;
-	list_for_each_entry(crtc,
-		&ddev->mode_config.crtc_list, head) {
-		radeon_crtc = to_radeon_crtc(crtc);
-		if (radeon_crtc->enabled) {
-			rdev->pm.active_crtcs |= (1 << radeon_crtc->crtc_id);
-			rdev->pm.active_crtc_count++;
+	if (rdev->num_crtc && rdev->mode_info.mode_config_initialized) {
+		list_for_each_entry(crtc,
+				    &ddev->mode_config.crtc_list, head) {
+			radeon_crtc = to_radeon_crtc(crtc);
+			if (radeon_crtc->enabled) {
+				rdev->pm.active_crtcs |= (1 << radeon_crtc->crtc_id);
+				rdev->pm.active_crtc_count++;
+			}
 		}
 	}
 
@@ -1478,12 +1480,14 @@
 	/* update active crtc counts */
 	rdev->pm.dpm.new_active_crtcs = 0;
 	rdev->pm.dpm.new_active_crtc_count = 0;
-	list_for_each_entry(crtc,
-		&ddev->mode_config.crtc_list, head) {
-		radeon_crtc = to_radeon_crtc(crtc);
-		if (crtc->enabled) {
-			rdev->pm.dpm.new_active_crtcs |= (1 << radeon_crtc->crtc_id);
-			rdev->pm.dpm.new_active_crtc_count++;
+	if (rdev->num_crtc && rdev->mode_info.mode_config_initialized) {
+		list_for_each_entry(crtc,
+				    &ddev->mode_config.crtc_list, head) {
+			radeon_crtc = to_radeon_crtc(crtc);
+			if (crtc->enabled) {
+				rdev->pm.dpm.new_active_crtcs |= (1 << radeon_crtc->crtc_id);
+				rdev->pm.dpm.new_active_crtc_count++;
+			}
 		}
 	}