drm/radeon/dce4+: don't use radeon_crtc for vblank callback

commit 4a15903d upstream.

This might be called before we've allocated the radeon_crtcs
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/gpu/drm/radeon/evergreen.c

@@ -37,6 +37,16 @@
 #define EVERGREEN_PFP_UCODE_SIZE 1120
 #define EVERGREEN_PM4_UCODE_SIZE 1376
 
+static const u32 crtc_offsets[6] =
+{
+	EVERGREEN_CRTC0_REGISTER_OFFSET,
+	EVERGREEN_CRTC1_REGISTER_OFFSET,
+	EVERGREEN_CRTC2_REGISTER_OFFSET,
+	EVERGREEN_CRTC3_REGISTER_OFFSET,
+	EVERGREEN_CRTC4_REGISTER_OFFSET,
+	EVERGREEN_CRTC5_REGISTER_OFFSET
+};
+
 static void evergreen_gpu_init(struct radeon_device *rdev);
 void evergreen_fini(struct radeon_device *rdev);
 void evergreen_pcie_gen2_enable(struct radeon_device *rdev);
@@ -101,17 +111,19 @@ void evergreen_fix_pci_max_read_req_size(struct radeon_device *rdev)
 
 void dce4_wait_for_vblank(struct radeon_device *rdev, int crtc)
 {
-	struct radeon_crtc *radeon_crtc = rdev->mode_info.crtcs[crtc];
 	int i;
 
-	if (RREG32(EVERGREEN_CRTC_CONTROL + radeon_crtc->crtc_offset) & EVERGREEN_CRTC_MASTER_EN) {
+	if (crtc >= rdev->num_crtc)
+		return;
+
+	if (RREG32(EVERGREEN_CRTC_CONTROL + crtc_offsets[crtc]) & EVERGREEN_CRTC_MASTER_EN) {
 		for (i = 0; i < rdev->usec_timeout; i++) {
-			if (!(RREG32(EVERGREEN_CRTC_STATUS + radeon_crtc->crtc_offset) & EVERGREEN_CRTC_V_BLANK))
+			if (!(RREG32(EVERGREEN_CRTC_STATUS + crtc_offsets[crtc]) & EVERGREEN_CRTC_V_BLANK))
 				break;
 			udelay(1);
 		}
 		for (i = 0; i < rdev->usec_timeout; i++) {
-			if (RREG32(EVERGREEN_CRTC_STATUS + radeon_crtc->crtc_offset) & EVERGREEN_CRTC_V_BLANK)
+			if (RREG32(EVERGREEN_CRTC_STATUS + crtc_offsets[crtc]) & EVERGREEN_CRTC_V_BLANK)
 				break;
 			udelay(1);
 		}