drm/imx: ipuv3-plane: Switch EBA buffer only when we don't need modeset

We added active plane reconfiguration support by forcing a full modeset
operation.  So, looking at old_plane_state->fb to determine whether we need to
switch EBA buffer(for hardware double buffering) in ipu_plane_atomic_set_base()
or not is no more correct.  Instead, we should do that only when we don't need
modeset, otherwise, we initialize the two EBA buffers with the buffer address.

Fixes: c6c1f9bc798b ("drm/imx: Add active plane reconfiguration support")
Cc: stable@vger.kernel.org # 4.8
Signed-off-by: Liu Ying <gnuiyl@gmail.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

drivers/gpu/drm/imx/ipuv3-plane.c

@@ -108,6 +108,7 @@ static void ipu_plane_atomic_set_base(struct ipu_plane *ipu_plane,
 {
 	struct drm_plane *plane = &ipu_plane->base;
 	struct drm_plane_state *state = plane->state;
+	struct drm_crtc_state *crtc_state = state->crtc->state;
 	struct drm_framebuffer *fb = state->fb;
 	unsigned long eba, ubo, vbo;
 	int active;
@@ -149,7 +150,7 @@ static void ipu_plane_atomic_set_base(struct ipu_plane *ipu_plane,
 		break;
 	}
 
-	if (old_state->fb) {
+	if (!drm_atomic_crtc_needs_modeset(crtc_state)) {
 		active = ipu_idmac_get_current_buffer(ipu_plane->ipu_ch);
 		ipu_cpmem_set_buffer(ipu_plane->ipu_ch, !active, eba);
 		ipu_idmac_select_buffer(ipu_plane->ipu_ch, !active);