Appeal from the Circuit Court of Winnebago County. No. 99-CF-1708 Honorable Joseph G. McGraw, Judge, Presiding.
 The opinion of the court was delivered by: Justice Byrne
 A jury found defendant, Charles Smith, guilty of burglary (720 ILCS 5/19--1 (West 1998)), a Class 2 felony. The trial court imposed a 24-year, Class X prison term based, in part, on defendant's criminal history. On direct appeal, defendant argued that (1) his sentence was excessive, (2) his trial counsel was ineffective and prejudiced against him, and (3) the trial court erroneously admitted certain evidence. This court affirmed the conviction and sentence. People v. Smith, No. 2--00--0461 (2001) (unpublished order under Supreme Court Rule 23).
 Defendant filed a pro se petition for relief under the Post-Conviction Hearing Act (Act) (725 ILCS 5/122--1 et seq. (West 2002)), alleging that (1) he was denied pretrial notice under section 111--3(c) of the Code of Criminal Procedure of 1963 (Code of Criminal Procedure) (725 ILCS 5/111--3(c) (West 1998)) that the State intended to seek a Class X sentence and (2) section 5--5--3(c)(8) of the Unified Code of Corrections (730 ILCS 5/5--5--3(c)(8) (West 1998)) violated his right to equal protection under the law because it irrationally prescribes harsher sentences for repeat offenders if they are at least 21 years old.
 The trial court dismissed the petition at the first stage of post-conviction review, entering a written order entitled, "ORDER DISMISSING POST CONVICTION PETITION AS 'FRIVOLOUS AND/OR PATENTLY WITHOUT MERIT.' " The court concluded that "defendant raised no new constitutionally cognizable claims. The sum and substance of defendant's claims were raised at trial, post-trial, and on direct appeal and defendant is thereby barred from relitigating the same issues."
 Defendant appealed, and the trial court appointed the office of the State Appellate Defender to represent him. The Appellate Defender moved to withdraw as counsel, and we denied the motion and directed counsel to brief any potentially meritorious issues. Defendant now argues that it is unclear whether the trial court dismissed the petition on the basis of res judicata or frivolousness, and that this ambiguity mandates a reversal and a remand for further proceedings in the trial court. The State contends that the trial court dismissed the petition based on frivolousness and alternatively argues that we may review the merits of the petition de novo.
 Courts have emphasized that post-conviction proceedings are designed to permit inquiry into constitutional issues involved in the original conviction and sentence that were not, nor could have been, adjudicated previously on direct appeal. People v. Lucas, 203 Ill. 2d 410, 417-18 (2002); People v. Cleveland, 342 Ill. App. 3d 912, 914 (2003). The Act provides that if the trial court finds that a post-conviction petition is "frivolous or is patently without merit," the court shall summarily dismiss the petition "in a written order, specifying the findings of fact and conclusions of law it made in reaching its decision." 725 ILCS 5/122--2.1(a)(2) (West 2002).
 Defendant cites People v. Boclair, 202 Ill. 2d 89 (2002), for the proposition that "a court may not dismiss a petition on the basis of untimeliness, waiver, or res judicata." In People v. McCain, 312 Ill. App. 3d 529, 531 (2000), a case consolidated with Boclair in the supreme court, the trial court summarily dismissed a post-conviction petition based on three factors: untimeliness, waiver, and res judicata. The Appellate Court, Fifth District, reversed the dismissal, holding that the trial court could not consider untimeliness, waiver, or res judicata at the initial stage of post-conviction proceedings. Our supreme court affirmed the appellate court's ruling, concluding only that the trial court should not have considered the timeliness issue. Boclair, 202 Ill. 2d at 113. The supreme court did not comment on whether a trial court may cite waiver or res judicata when summarily dismissing a post-conviction petition. People v. Smith, 341 Ill. App. 3d 530, 536 (2003) ("Boclair does not specifically address the defenses of waiver and res judicata").
 The waiver issue was squarely addressed in Cleveland, where this court held that "waiver is not a proper basis for summarily dismissing a post-conviction petition." Cleveland, 342 Ill. App. 3d at 915. This court has yet to consider whether a trial court may cite res judicata as a basis for dismissing a post-conviction petition at the initial stage of the proceedings, and the appellate court has not reached a consensus on the question. Compare Smith, 341 Ill. App. 3d at 537 (First District, First Division) ("we do not necessarily agree that Boclair compels similar treatment for the defenses of waiver and res judicata as it does for timeliness"), with People v. McGhee, 337 Ill. App. 3d 992, 995-96 (2003) (First District, Third Division) (the trial court may not rely on res judicata or waiver to summarily dismiss a first-stage post-conviction petition because, like timeliness, res judicata and waiver constitute procedural bars and do not address the substantive merit of the defendant's claims).
 In People v. Lucas, 203 Ill. 2d 410 (2002), the supreme court reviewed the summary dismissal of a post-conviction petition and stated that "[a]ny issues considered by the court on direct appeal are barred by the doctrine of res judicata, and issues which could have been raised on direct appeal are deemed waived." Lucas, 203 Ill. 2d at 418. One might interpret Lucas as authorizing a circuit court to cite res judicata as a basis for dismissing a post-conviction petition at the initial stage of the proceedings. However, in light of our decision in Cleveland, we need not effect such an interpretation.
 In Cleveland, we held that the appellate court may independently determine that a post-conviction petition is frivolous and patently without merit based on the totality of the record. Cleveland, 342 Ill. App. 3d at 916; see also People v. Little, 335 Ill. App. 3d 1046 (2003) (Fourth District). We reject defendant's request to abandon our holding in Cleveland because he offers no persuasive argument for doing so. Because " 'it is not the trial court's reasoning which is the subject of this court's review, but, rather, its judgment,' " we review the correctness of the dismissal of the petition de novo. See Cleveland, 342 Ill. App. 3d at 915, quoting People v. Norks, 137 Ill. App. 3d 1078, 1082 (1985).
 In his petition, defendant claims that he was denied notice under section 111--3(c) of the Code of Criminal Procedure that the State intended to seek a Class X sentence. Section 111--3(c) provides as follows:
"When the State seeks an enhanced sentence because of a prior
conviction, the charge shall also state the intention to seek an
enhanced sentence and shall state such prior conviction so as to
give notice to the defendant. *** For the purposes of this
Section, 'enhanced sentence' means a sentence which is increased by
a prior conviction from one classification of offense to another
higher level classification of offense set forth in Section 5--5--1
of the 'Unified Code of Corrections' ***; it does not include an
increase in the sentence applied within the same level of
classification of offense." 725 ILCS 5/111--3(c) (West 2002).
 As in this case, the defendant in People v. Jameson, 162 Ill. 2d 282 (1994), was convicted of burglary, a Class 2 felony, and sentenced as a Class X offender based on his prior felony convictions. Jameson, 162 Ill. 2d at 284. The defendant argued that, because the charging instrument did not mention the possibility of a Class X sentence, he was denied his right to notice under section 111--3(c) of the Code of Criminal Procedure. The supreme court rejected the argument and held as follows:
"When the language of section 111--3(c) is considered in light
of the legislative history of that statute, it is evident that the
legislature intended that statute to reach those instances in which
a prior conviction elevates the classification of the offense with
which a defendant is charged and convicted, rather than simply the
sentence imposed. The legislature did not intend to require the
State to give defendants pretrial notice that they would ...