What is the duty of a judge to suspend trial proceedings and conduct a competency hearing?

"Both federal due process and state law require a trial judge to suspend trial proceedings and conduct a competency hearing whenever the court is presented with substantial evidence of incompetence, that is, evidence that raises a reasonable or bona fide doubt concerning the defendant's competence to stand trial. [Citations.] The court's duty to conduct a competency hearing may arise at any time prior to judgment. [Citation.] Evidence of incompetence may emanate from several sources, including the defendant's demeanor, irrational behavior, and prior mental evaluations. [Citations.]" (People v. Rogers (2006) 39 Cal.4th 826, 847.)