What are the consequences of a revocation of probation for abuse of discretion?

^1. We review revocation of probation for abuse of discretion and, likewise, "review rulings on whether hearsay was improperly admitted at a violation hearing for abuse of discretion." (People v. Abrams (2007) 158 Cal.App.4th 396, 400 (Abrams).) An abuse of discretion occurs, however, when a trial court fails to apply, or to comply with, controlling legal principles. (See People v. Bolton (1979) 23 Cal.3d 208, 216 ["Discretion is compatible only with decisions 'controlled by sound principles of law, . . . free from partiality, not swayed by sympathy or warped by prejudice. . . .' "].)