Cal. PEN § 1381.5

Whenever a defendant has been convicted of a crime and has entered upon a term of imprisonment therefor in a federal correctional institution located in this state, and at the time of entry upon such term of imprisonment or at any time during such term of imprisonment there is pending in any court of this state any criminal indictment, information, complaint, or any criminal proceeding wherein the defendant remains to be sentenced the district attorney of the county in which such matters are pending, upon receiving from such defendant a request that he be brought to trial or for sentencing, shall promptly inquire of the warden or other head of the federal correctional institution in which such defendant is confined whether and when such defendant can be released for trial or for sentencing. If an assent from authorized federal authorities for release of the defendant for trial or sentencing is received by the district attorney he shall bring him to trial or sentencing within 90 days after receipt of such assent, unless the federal authorities specify a date of release after 90 days, in which event the district attorney shall bring the prisoner to trial or sentencing at such specified time, or unless the defendant requests, in open court, and receives, or, in open court, consents to, a continuance, in which event he may be brought to trial or sentencing within 90 days from such request or consent.

If a defendant is not brought to trial or for sentencing as provided by this section, the court in which the action is pending shall, on motion or suggestion of the district attorney, or representative of the United States, or the defendant or his counsel, dismiss the action.