Now comes news that the California Supreme Court has approved revisions to the California Rules of Professional Conduct governing the ethical duties of prosecutors in California by revising Rule 5-110 to include the obligation to disclose exculpatory evidence. If you are wondering how this was not part of the rule already, it is because California remains the only state that has not fully adopted the ABA Model Rules. Popehat has the details here.
Interestingly, in contrast with the decision in Louisiana, the comment to the new California rule implies that the duty to disclose is broader than the duty imposed by Brady:
 The disclosure obligations in paragraph (d) are not limited to evidence or information that is material as defined by Brady v. Maryland . . . and its progeny. For example, these obligations include, at a minimum, the duty to disclose impeachment evidence or information that a prosecutor knows or reasonably should know casts significant doubt on the accuracy or admissibility of witness testimony on which the prosecution intends to rely. . . .