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 0E17BCD5854 for ; Wed, 7 Jan 2026 10:48:59 +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:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=6oomKfPvwsh9H6e02fPSNWw1BvNK9xml8xEHtUKSHfo=; b=rwKFH7YRcAHwrEjyG7//3UqfYI klB0AsRCkAfsAc8+RSn7nG5Cueg3z5dt3eD5NNGv5hwQPlRjvPu8GN3pwrV+sPURMdT2htQwiC+A6 DnhmkVJNffxBlCGjO8F1lKiEBjI/5Wev46tUz9KUi2H3mYku1mCwmnf0u8MqpNC91vBa6ygCRalfF sl4+WqlQ+Z4QV5fIyUTTBkDiZqFeio0+wZ05yWh93bfhw6gTiYhExiqmlvX5is+flprS29I+AIb3p Ds243+Q/0UOthKZXn39vve1v50MzcihjjIh7NZwMEJWVj52cnevp0C+jFltJPRqidN7JTxdWX/I9c s6SZWxLw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vdR5u-0000000Ek69-1ZYa; Wed, 07 Jan 2026 10:48:50 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vdR5t-0000000Ek5x-1iQM for linux-arm-kernel@lists.infradead.org; Wed, 07 Jan 2026 10:48:49 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 7743A6013A; Wed, 7 Jan 2026 10:48:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EC8E9C4CEF7; Wed, 7 Jan 2026 10:48:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767782928; bh=elz7b0vRGAXydvDoYJOal+0LEqRABOCnweSBG07nrMo=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=GAs5p4G1TrQaJQMQTBBrsEsxNhMhkIDdQ0ETldQ3iU6Z4EbbmdtUzplu/vcqt75jS eqQdmfFcLf/OJi8OLgbmKIxOmWy6G3TBBqDR3mEX7TMUXJsPa6LrMe3VRKkJJDRZuc hzbncfezVqvkHRuK8+TaSx/w7xzV7UYL0OszyJJKgvvrEni0NRRnpS50YLwHPG7o3U peB3SoNvdgh0TLmlZVJy8eyXP8gU7x16PxDoBbx4rIn9scWnfgp3Lgu8HSbrnPqhpt 8MRTWAnisJvv7toMRPIgCe6rydcvj4HKNX09V0HM+AlHdvC3PDePgb1ah11pBaCZoa DWr8d82WmcrPw== Message-ID: <04d8766f-0f79-409b-9290-3170e99e9750@kernel.org> Date: Wed, 7 Jan 2026 11:48:42 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/2] dt-bindings: watchdog: fsl-imx: document continue in low power mode To: Nandor Han Cc: wim@linux-watchdog.org, linux@roeck-us.net, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com, linux-watchdog@vger.kernel.org, devicetree@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20251229145000.421426-1-nandor.han@gehealthcare.com> <20251229145000.421426-3-nandor.han@gehealthcare.com> <20251230-hidden-okapi-of-reputation-6ef8be@quoll> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit 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 On 07/01/2026 10:12, Nandor Han wrote: > > On 12/30/25 14:34, Krzysztof Kozlowski wrote: >> CAUTION: This email originated from outside of GE HealthCare. Only open links or attachments if you trust the sender. Report suspicious emails using Outlook’s “Report” button. >> >> On Mon, Dec 29, 2025 at 04:50:00PM +0200, Nandor Han wrote: >>> Property "fsl,wdt-continue-in-low-power" allows the watchdog to continue >>> running in low power modes (STOP and DOZE). By default, the watchdog is >>> suspended in these modes. This property provides the option to keep the >>> watchdog active during low power states when needed. >> And why exactly would that be a DT property? If system is sleeping >> (assuming this is what you meant by low power), no one will pet the dog, >> thus watchdog makes no sense. > > Thanks for the feedback Krzysztof and Guenter. > > In our case, low-power mode is disabled. However, we have identified that under certain conditions, If your system has low power mode disabled, then you do not need this property - you already know that watchdog must continue (or whatever you want to achieve here). > specifically during simulated high-load scenarios, the device becomes unresponsive because it enters > one of these power states. Device as watchdog? I really do not understand your explanations, but for sure system load is not relevant to DT property. > >> Otherwise I fail to see how this is a hardware property and we do not >> accept SW properties (see writing bindings, numerous presentations). > > Our system is based on the i.MX7D CPU and the watchdog peripheral supports the configuration: > > (From i.MX 7Dual Applications Processor Reference Manual, Rev. 1, 01/2018, page: 1174) > --- > WDZST > Watchdog Low Power. Determines the operation of the WDOG during low-power modes. This bit is write > once-only. > --- > Given that our system does not support low-power modes, we intend to enable the watchdog across all power > states to ensure the device can recover properly under these conditions. That's not what your property said. Your property said watchdog should continue in low power modes. So when system enters low power mode, how the watchdog petting would work? Now you claim you want to enable it in low power mode but you do not have low power mode? Does not make sense to me at all. Best regards, Krzysztof