From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7D41BCA0EDB for ; Tue, 12 Aug 2025 19:23:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Message-ID:Date:To:Cc:From: Subject:References:In-Reply-To:Content-Transfer-Encoding:MIME-Version: Content-Type:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=3167PLa7qi5Lws1yxuv9LeqRuM6ayJCfXH3FRvZSxCg=; b=DwkLwSGvRWPz08RFX+IS6C6Ax3 BgSkOnZgxwI7BM7vGXeHN82N4iZIRUxOWKc+ojTko0efGZyHX+4xNgnzNmDXotA5cEv/zMNZUIEcg buWIZki3csR8OGEmFQ1GgWhtGhevdxph3xX0P14RxbWKeVQdQtrF8PWxK8sEQdDSrpd84XFNkar7n HSZ1aooVp3h+oF9p0UABlPtjb+U9FcspTCBQarkWJxU/kLynxeXZuLauHH+TqNLlePa8gl0KjLwdJ XmLIJOLEAO7kA71wnWo0x93gn6ca2l03j+yQj6uosvSfTIVaRxcblvuGEdx+B9jL/64Yqf0Nv8oiY +OQqA0dQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uluai-0000000BmvF-1WLO; Tue, 12 Aug 2025 19:23:24 +0000 Received: from perceval.ideasonboard.com ([213.167.242.64]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1ulqWN-0000000B8jO-3RkX; Tue, 12 Aug 2025 15:02:40 +0000 Received: from ideasonboard.com (unknown [IPv6:2a00:6020:448c:6c00:7c24:e2bc:68da:c990]) by perceval.ideasonboard.com (Postfix) with UTF8SMTPSA id 6B4F64A4; Tue, 12 Aug 2025 17:01:43 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1755010903; bh=wR0BxUp4dy33m59/4v222C9B6JZd9Ir0fQjUINH+5+c=; h=In-Reply-To:References:Subject:From:Cc:To:Date:From; b=v4s0yHvZaZ/6VupsHQsCY3EgCCkGo9R/3YHqllY2jygzLaf0K8PIkymJitkGk9jaj Rl12W765kA/4eJ20Rz2rC7kdUYX3/Xa58+xjsfIBEPzMKd2l3hdzPQX321ewN3H26k 6FEmlVdW+jb8tvvbaTc3wdJMJhBaUpzu7khXaGkY= Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable In-Reply-To: <20250812103243.GK30054@pendragon.ideasonboard.com> References: <175308758352.3134829.9472501038683860006@localhost> <175326599663.2811177.16620980968274114885@localhost> <175344176070.2811177.10693943493658922992@localhost> <20250812103243.GK30054@pendragon.ideasonboard.com> Subject: Re: FYI: i.MX8MP ISP (RKISP1) MI registers corruption: resolved From: Stefan Klug Cc: Dafna Hirschfeld , Heiko Stuebner , Paul Elder , Jacopo Mondi , Ondrej Jirman , linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org To: Krzysztof =?utf-8?q?Ha=C5=82asa?= , Laurent Pinchart Date: Tue, 12 Aug 2025 17:02:33 +0200 Message-ID: <175501095338.74722.11604545949710100799@localhost> User-Agent: alot/0.12.dev8+g2c003385c862.d20250602 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250812_080239_995242_4759D69A X-CRM114-Status: GOOD ( 25.25 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Krzysztof, hi Laurent, Quoting Laurent Pinchart (2025-08-12 12:32:43) > Hi Krzysztof, >=20 > On Tue, Aug 12, 2025 at 07:54:46AM +0200, Krzysztof Ha=C5=82asa wrote: > > Hi Stefan et al, > >=20 > > BTW I've added Lucas Stach and Shawn Guo to "Cc" list. > >=20 > > The problem is the CPU core power supply voltage :-) >=20 > Ah, the dreadful overdrive mode. >=20 > > - while the reference manual specifies the max ISP and MEDIA clocks at > > 500 MHz, the datasheets show this requires the "overdrive" mode =3D > > increased CPU power supply voltage. In "normal" mode the ISPs are > > limited to 400 MHz (there are other limits, too). > >=20 > > - I've tried lowering the clock rate after booting the systems (with > > a CCM register write), but it didn't fix the problem. I guess some > > reset logic is affected here, and the (lower) clock rate must be set > > right from the start, in the DT. >=20 > That's interesting. I wouldn't have expected that. >=20 > > - anyway, lowering the frequencies of ISP and MEDIA root clocks fixes > > the ISP2 MI corruption. I'm currently investigating PMIC settings > > (both my Compulab and SolidRun modules use PCA9450C PMICs), so perhaps > > I'll be able to use the higher 500 MHz clocks. It doesn't matter much, > > though. > >=20 > > - the question is if we should lower the clocks in the main imx8mp.dtsi > > DT file, or the overdrive mode should stay there, and the changes > > should be made to the individual board files, or maybe the U-Boot > > configs (PMIC output voltages) should be changed etc. >=20 > I think it would make sense to lower the default clock frequencies, and > provide an overlay to enable overdrive mode. >=20 > It's also interesting that the issue only affected the second ISP, as > the first one should also be limited to 400 MHz in normal mode. I support that. As a side note, there is already imx8mp-nominal.dtsi which is only used by one board. That dtsi also uses the fsl,operating-mode property which enables additional clock checks. So I ask myself if the default imx8mp.dtsi should specify overdrive mode, or if we should add a imx8mp-overdrive.dtsi (then we should possibly rename them to imx8mp-mode-xxx.dtsi so that they sit side by side) to make it easier to create overlays for both cases.=20 Best regards, Stefan >=20 > --=20 > Regards, >=20 > Laurent Pinchart