In mtk_crtc_ddp_config(), mtk_crtc will use some configuration flags to
generate instructions to cmdq_handle, such as:
state->pending_config
mtk_crtc->pending_planes
plane_state->pending.config
mtk_crtc->pending_async_planes
plane_state->pending.async_config
These configuration flags may be set to false when a GCE IRQ comes calling
ddp_cmdq_cb(). This may result in missing prepare instructions,
especially if mtk_crtc_update_config() with the flase need_vblank (no need
to wait for vblank) cases.
Therefore, use the mtk_crtc->config_updating flag set at the beginning of
mtk_crtc_update_config() to ensure that these configuration flags won't be
changed when the mtk_crtc_ddp_config() is preparing instructions.
Fixes: 7f82d9c43879 ("drm/mediatek: Clear pending flag when cmdq packet is done")
Signed-off-by: Jason-JH.Lin <jason-jh.lin@xxxxxxxxxxxx>