Two years ago John Desmarais left Kirkland & Ellis, acquired 4,500 patents, and opened a patent licensing company called Round Rock Research. He also debuted a small law firm called Desmarais LLP that represents Round Rock in litigation. Now one of Round Rock’s adversaries is raising ethical objections to Desmarais’ unusual role as both Round Rock’s CEO and head of its go-to law firm.

Dell Inc. filed a petition for a writ of mandamus with the U.S. Court of Appeals for the Federal Circuit on Thursday, urging the court to block the entire Desmarais LLP law firm from accessing proprietary information Dell must provide to Round Rock during discovery. Dell, which is represented by Winston & Strawn and Farella Braun & Martel, argues that the Desmarais LLP lawyers might share the proprietary information with founder Desmarais, who in turn may use it to bolster Round Rock’s business ambitions.