drm/radeon/r5xx-r7xx: don't use radeon_crtc for vblank callback (v2)

This might be called before we've allocated the radeon_crtcs

v2: fix typo in array size
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/rs600.c

@@ -46,19 +46,27 @@
 void rs600_gpu_init(struct radeon_device *rdev);
 int rs600_mc_wait_for_idle(struct radeon_device *rdev);
 
+static const u32 crtc_offsets[2] =
+{
+	0,
+	AVIVO_D2CRTC_H_TOTAL - AVIVO_D1CRTC_H_TOTAL
+};
+
 void avivo_wait_for_vblank(struct radeon_device *rdev, int crtc)
 {
-	struct radeon_crtc *radeon_crtc = rdev->mode_info.crtcs[crtc];
 	int i;
 
-	if (RREG32(AVIVO_D1CRTC_CONTROL + radeon_crtc->crtc_offset) & AVIVO_CRTC_EN) {
+	if (crtc >= rdev->num_crtc)
+		return;
+
+	if (RREG32(AVIVO_D1CRTC_CONTROL + crtc_offsets[crtc]) & AVIVO_CRTC_EN) {
 		for (i = 0; i < rdev->usec_timeout; i++) {
-			if (!(RREG32(AVIVO_D1CRTC_STATUS + radeon_crtc->crtc_offset) & AVIVO_D1CRTC_V_BLANK))
+			if (!(RREG32(AVIVO_D1CRTC_STATUS + crtc_offsets[crtc]) & AVIVO_D1CRTC_V_BLANK))
 				break;
 			udelay(1);
 		}
 		for (i = 0; i < rdev->usec_timeout; i++) {
-			if (RREG32(AVIVO_D1CRTC_STATUS + radeon_crtc->crtc_offset) & AVIVO_D1CRTC_V_BLANK)
+			if (RREG32(AVIVO_D1CRTC_STATUS + crtc_offsets[crtc]) & AVIVO_D1CRTC_V_BLANK)
 				break;
 			udelay(1);
 		}