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 8B1B8CCFA04 for ; Wed, 5 Nov 2025 06:51:45 +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=AlUFFi5rfJVf2y32pRIQ+FZuh2lcRqrpHCjJPK/PxcM=; b=ymBn2H4791X7Vq6WkW+hiN93wC KfgDObfdvSKE/PKlNXHgGw0n31c0pXSPko33a+7AvCHBWR9O/qVP9yEtsf6nUg4JMvwwno1Dh+/7V gtxWuTEp6k5DgZurCSiC/HQjYNYn6ts+XpKGzbHbhZ4nL9nzCfVFOiT7udLGpMcXwupJkvALd3fAu Gy8AMja/sY/JicOhyegCQBbDFl9UycYE3AVR71waYeZfoHYVsh56qJaU15WmTJHSAClg3OlDpUf8i YwtI3rQKo0RBZ6WQpfGbtBSzBFshNTSbVHFcH7RhvAHeozUXRssjQnlzxGNda0UsUevIuAcv6SueO naQiYfgw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vGXMn-0000000D61i-1gYA; Wed, 05 Nov 2025 06:51:37 +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 1vGXMk-0000000D61G-1Bkj; Wed, 05 Nov 2025 06:51:35 +0000 Received: from mail.ideasonboard.com (unknown [IPv6:2401:4900:1c67:1e6b:c21c:d386:b74e:e876]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 53DE3446; Wed, 5 Nov 2025 07:49:34 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1762325374; bh=28fwD/DeHigm3/oxHExJ1zgx8z4FLlzDSl8G0AySjY8=; h=In-Reply-To:References:Subject:From:Cc:To:Date:From; b=g3IvUDxEb1PbSXQm9Kgk3dE8t7oCPugrK4wVg5SS6cq3hvKwwKBC38U4eBt9Fudyk 7QAfPQLJhV0UOKe31uBeAA9TYfbqnPavatyZ+hX2p+zHde9qD9R/8q6zCK45+BnFCp eOx5AB2sJHzV8t0yb1haLYa5Hr+4HW5V9iRfHXMc= Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable In-Reply-To: <3e538ec1-37f6-416c-bc04-6f21a4d31748@broadcom.com> References: <20251028-rpi-isp-clk-v1-1-2a54fecb495c@ideasonboard.com> <3e538ec1-37f6-416c-bc04-6f21a4d31748@broadcom.com> Subject: Re: [PATCH] clk: bcm: rpi: Mark ISP clock as critical From: Jai Luthra Cc: linux-clk@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org To: Broadcom internal kernel review list , Florian Fainelli , =?utf-8?q?Ma=C3=ADra?= Canal , Michael Turquette , Stefan Wahren , Stephen Boyd Date: Wed, 05 Nov 2025 12:21:23 +0530 Message-ID: <176232548379.1167490.1126479868042439951@freya> User-Agent: alot/0.12.dev28+gd2c823fe X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251104_225134_471167_56115F56 X-CRM114-Status: GOOD ( 18.96 ) 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 Florian, Quoting Florian Fainelli (2025-11-05 03:50:23) > On 10/28/25 04:46, Jai Luthra wrote: > > The ISP clock should also be marked critical to prevent the clock > > framework from disabling it on boot, which can lead to bus lockups when > > the kernel tries to submit buffers to the VC4 ISP firmware. >=20 > The commit message suggests that the driver that interfaces with the VC4 = > ISP firmware is not ensuring that the clock remains enabled for the=20 > duration of the transactions. That would be a driver bug, would not it? >=20 Yes, from https://github.com/raspberrypi/linux/issues/7100#issuecomment-346= 7699055 the VC4 firmware should be responsible for stopping and starting that clock when necessary. The downstream bcm2835-isp linux driver currently does not consume this clock at all, so I'm not sure if the cleaner solution is to drop this altogether from linux, or mark it as a consumer, along with fixing the firmware driver. > >=20 > > Link: https://github.com/raspberrypi/linux/issues/7100 > > Fixes: 919d6924ae9b ("clk: bcm: rpi: Turn firmware clock on/off when pr= eparing/unpreparing") > > Signed-off-by: Jai Luthra > > --- > > drivers/clk/bcm/clk-raspberrypi.c | 1 + > > 1 file changed, 1 insertion(+) > >=20 > > diff --git a/drivers/clk/bcm/clk-raspberrypi.c b/drivers/clk/bcm/clk-ra= spberrypi.c > > index 1a9162f0ae31e330c46f6eafdd00350599b0eede..dcc3ae5fb91650b042d52f0= 2499922786b43afde 100644 > > --- a/drivers/clk/bcm/clk-raspberrypi.c > > +++ b/drivers/clk/bcm/clk-raspberrypi.c > > @@ -151,6 +151,7 @@ raspberrypi_clk_variants[RPI_FIRMWARE_NUM_CLK_ID] = =3D { > > [RPI_FIRMWARE_ISP_CLK_ID] =3D { > > .export =3D true, > > .minimize =3D true, > > + .flags =3D CLK_IS_CRITICAL, > > }, > > [RPI_FIRMWARE_PIXEL_BVB_CLK_ID] =3D { > > .export =3D true, > >=20 > > --- > > base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787 > > change-id: 20251028-rpi-isp-clk-eb5c48346e51 > >=20 > > Best regards, >=20 >=20 > --=20 > Florian Thanks, Jai