@@ -65,6 +65,20 @@ static const struct debugfs_reg32 crtc_regs[] = {
 	VC4_REG32(PV_HACT_ACT),
 };
 
+static unsigned int
+vc4_crtc_get_cob_allocation(struct vc4_dev *vc4, unsigned int channel)
+{
+	u32 dispbase = HVS_READ(SCALER_DISPBASEX(channel));
+	/* Top/base are supposed to be 4-pixel aligned, but the
+	 * Raspberry Pi firmware fills the low bits (which are
+	 * presumably ignored).
+	 */
+	u32 top = VC4_GET_FIELD(dispbase, SCALER_DISPBASEX_TOP) & ~3;
+	u32 base = VC4_GET_FIELD(dispbase, SCALER_DISPBASEX_BASE) & ~3;
+
+	return top - base + 4;
+}
+
 static bool vc4_crtc_get_scanout_position(struct drm_crtc *crtc,
 					  bool in_vblank_irq,
 					  int *vpos, int *hpos,

@@ -74,6 +88,7 @@ static bool vc4_crtc_get_scanout_position(struct drm_crtc *crtc,
 	struct drm_device *dev = crtc->dev;
 	struct vc4_dev *vc4 = to_vc4_dev(dev);
 	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
+	unsigned int cob_size;
 	u32 val;
 	int fifo_lines;
 	int vblank_lines;

@@ -109,8 +124,9 @@ static bool vc4_crtc_get_scanout_position(struct drm_crtc *crtc,
 			*hpos += mode->crtc_htotal / 2;
 	}
 
+	cob_size = vc4_crtc_get_cob_allocation(vc4, vc4_crtc->channel);
 	/* This is the offset we need for translating hvs -> pv scanout pos. */
-	fifo_lines = vc4_crtc->cob_size / mode->crtc_hdisplay;
+	fifo_lines = cob_size / mode->crtc_hdisplay;
 
 	if (fifo_lines > 0)
 		ret = true;

@@ -823,22 +839,6 @@ static void vc4_set_crtc_possible_masks(struct drm_device *drm,
 	}
 }
 
-static void
-vc4_crtc_get_cob_allocation(struct vc4_crtc *vc4_crtc)
-{
-	struct drm_device *drm = vc4_crtc->base.dev;
-	struct vc4_dev *vc4 = to_vc4_dev(drm);
-	u32 dispbase = HVS_READ(SCALER_DISPBASEX(vc4_crtc->channel));
-	/* Top/base are supposed to be 4-pixel aligned, but the
-	 * Raspberry Pi firmware fills the low bits (which are
-	 * presumably ignored).
-	 */
-	u32 top = VC4_GET_FIELD(dispbase, SCALER_DISPBASEX_TOP) & ~3;
-	u32 base = VC4_GET_FIELD(dispbase, SCALER_DISPBASEX_BASE) & ~3;
-
-	vc4_crtc->cob_size = top - base + 4;
-}
-
 int vc4_crtc_init(struct drm_device *drm, struct vc4_crtc *vc4_crtc,
 		  const struct drm_crtc_funcs *crtc_funcs,
 		  const struct drm_crtc_helper_funcs *crtc_helper_funcs)

@@ -870,7 +870,6 @@ int vc4_crtc_init(struct drm_device *drm, struct vc4_crtc *vc4_crtc,
 	 * implemented as private driver state in vc4_kms, not here.
 	 */
 	drm_crtc_enable_color_mgmt(crtc, 0, true, crtc->gamma_size);
-	vc4_crtc_get_cob_allocation(vc4_crtc);
 
 	for (i = 0; i < crtc->gamma_size; i++) {
 		vc4_crtc->lut_r[i] = i;

@@ -477,8 +477,6 @@ struct vc4_crtc {
 	u8 lut_r[256];
 	u8 lut_g[256];
 	u8 lut_b[256];
-	/* Size in pixels of the COB memory allocated to this CRTC. */
-	u32 cob_size;
 
 	struct drm_pending_vblank_event *event;