drm_crtc_helper_mode_valid_fixed
result = drm_crtc_helper_mode_valid_fixed(encoder->crtc, adjusted_mode, native_mode);
EXPORT_SYMBOL(drm_crtc_helper_mode_valid_fixed);
enum drm_mode_status drm_crtc_helper_mode_valid_fixed(struct drm_crtc *crtc,