Maryland Criminal Procedure Section 7-102
(a)   Subject to subsection (b) of this section, §§ 7-103 and 7-104 of this subtitle and Subtitle 2 of this title, a convicted person may begin a proceeding under this title in the circuit court for the county in which the conviction took place at any time if the person claims that:
(1)   the sentence or judgment was imposed in violation of the Constitution of the United States or the Constitution or laws of the State;
(2)   the court lacked jurisdiction to impose the sentence;
(3)   the sentence exceeds the maximum allowed by law; or
(4)   the sentence is otherwise subject to collateral attack on a ground of alleged error that would otherwise be available under a writ of habeas corpus, writ of coram nobis, or other common law or statutory remedy.
(b)   A person may begin a proceeding under this title if:
(1)   the person seeks to set aside or correct the judgment or sentence; and
(2)   the alleged error has not been previously and finally litigated or waived in the proceeding resulting in the conviction or in any other proceeding that the person has taken to secure relief from the person's conviction.