Maryland Code, Corporations and Associations § 4-504

(a) A close corporation may deny or restrict the voting rights of any of its stock as provided in this article.  Notwithstanding any denial or restriction, all stock has voting rights on any matter required by this title to be authorized by the affirmative vote of every stockholder or every subscriber for stock of a close corporation.

(b) Notwithstanding the provisions of § 2-104(b)(5) of this article, the charter of a close corporation may not lower the proportion of votes required to approve any action for which this title requires the affirmative vote or assent of every stockholder or every subscriber for stock of the corporation.