Discovery in misdeemanor cases in Illinois do NOT follow the Illinois Supreme Court Rules on discovery which only apply to felony cases.
The rules in misdemeanor cases are described in a case called People v. Schmidt, 56 Ill.2d 572 (1974). They required the states attorney to give the defense a 1) witness list, 2) copy of confessions, and 3) any exculpatory evidence (evidence that proves the defendant or suggests the defendant is not guilty).
The defendant is NOT obliged to provide the state anything including witness lists in misdemeanor discovery. The defendant’s witnesses can decide to refuse to speak to the state’s attorney’s investigators.
There are exceptions, but the state or defendant must ask for additional discovery by motion and have a hearing before the court about this issue.
The only change in the law was in a case called People v. Kladis, 2011 IL 110920 ¶ 23, 355 Ill.Dec. 933, 960 N.E.2d 1104 [#110920, 2011 IL 110920, 2011 Ill. Lexis 2236, 2011 IL 110920] where the court ruled that the state must also provide videos from police cars capturing the incident in discovery.
See this page describing all this in more detail.