Nature of proceeding and relation to other remedies

A proceeding under this rule displaces all post-trial remedies except posttrial motions under Rule 24 and appeal. Any other post-conviction petition seeking relief from a conviction or sentence shall be treated as a proceeding under this rule. Proceedings under this rule shall be governed by the Rules of Criminal Procedure, except that the trial court in its sole discretion may allow the taking of depositions for discovery or for use at trial.