From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zeus03.de (zeus03.de [194.117.254.33]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0288F396B99 for ; Wed, 14 Jan 2026 11:59:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=194.117.254.33 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768391976; cv=none; b=U5A9OW6Cm3tOs7Aib0bvS0fYHXoOcib6M6MerLO6kmooJoqXCaMcuk/q7vuZDbTiwNxqxuhcsL5F6EakcGeyQXTrTcaMB3pHYgyCKrCJrnwF89KktNBiR1rgZIdDIUbrwkvgnAO1rvihWKy8RIvPbZ1+B1FwJKbd06UJlpd6lUg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768391976; c=relaxed/simple; bh=2XvwYtXYU+Rubef0aBCZQFBdAsXFBc9YG5RxqQnD6vc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=UmXf2s/kCvdVljoSjDcCOnFWDHr9gew7cnlWa35avzJGVMgEpCmOTYYkde7lIN2NbLeY2IB6riQHgTL+4s1OGxjMKgjrgGI4Cq74uRBafMAAuCt2VqReRlo8Vi6If/rL5YyNFT573vWHYbbdCD56UDRPJtHCAHeVN9PFDr6In1s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sang-engineering.com; spf=pass smtp.mailfrom=sang-engineering.com; dkim=pass (2048-bit key) header.d=sang-engineering.com header.i=@sang-engineering.com header.b=JDhrYuve; arc=none smtp.client-ip=194.117.254.33 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sang-engineering.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sang-engineering.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sang-engineering.com header.i=@sang-engineering.com header.b="JDhrYuve" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= sang-engineering.com; h=date:from:to:cc:subject:message-id :references:mime-version:content-type:in-reply-to; s=k1; bh=DiiV rnvzlQr5Cq67SbrH7P4Pzbq4h86xOafA0L9a+yk=; b=JDhrYuve2lN91zc07CLA Y4qtiPhz8jRDv/LHeSwZlAtmMRAPR/WCafJDEsFBOEm5UTxH3otG7ksevUj1j+Xe 1rGdLnsbbX8xLeVRzR1B3YAjIEZAtGrP0i5lblpvxsPCgo5P6osaEmDMcMBxCBN2 6Wo2+b/pIRRYIxOm/XEVPFIfthGnnav8+pLWepNqMx8tKKvaPhGsvccIVO1G8O99 JU1Oe5e9CBc2k6ya3ffn+Bxaky0SmmxOqf2GQkcHVi52fm6rn+v90tRGSwFSyfTX 4EzFFr6eJPuursUVdbLW4ckOq2d9LjNRem0fXkL+aAawmTdkWE+z8rZwaxPOss6H 7A== Received: (qmail 2115980 invoked from network); 14 Jan 2026 12:59:29 +0100 Received: by mail.zeus03.de with UTF8SMTPSA (TLS_AES_256_GCM_SHA384 encrypted, authenticated); 14 Jan 2026 12:59:29 +0100 X-UD-Smtp-Session: l3s3148p1@HeXl1ldIIL8ujnsM Date: Wed, 14 Jan 2026 12:59:24 +0100 From: Wolfram Sang To: Carlos Song Cc: frank.li@nxp.com, aisheng.dong@nxp.com, andi.shyti@kernel.org, shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de, linux-i2c@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3] i2c: imx-lpi2c: change to PIO mode in system-wide suspend/resume progress Message-ID: References: <20251121030030.1844530-1-carlos.song@nxp.com> Precedence: bulk X-Mailing-List: linux-i2c@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251121030030.1844530-1-carlos.song@nxp.com> On Fri, Nov 21, 2025 at 11:00:30AM +0800, Carlos Song wrote: > EDMA resumes early and suspends late in the system power transition > sequence, while LPI2C enters the NOIRQ stage for both suspend and resume. > This means LPI2C resources become available before EDMA is fully resumed. > Once IRQs are enabled, a slave device may immediately trigger an LPI2C > transfer. If the transfer length meets DMA requirements, the driver will > attempt to use EDMA even though EDMA may still be unavailable. > > This timing gap can lead to transfer failures. To prevent this, force > LPI2C to use PIO mode during system-wide suspend and resume transitions. > This reduces dependency on EDMA and avoids using an unready DMA resource. > > Fixes: a09c8b3f9047 ("i2c: imx-lpi2c: add eDMA mode support for LPI2C") > Signed-off-by: Carlos Song > Reviewed-by: Frank Li Applied to for-current, thanks!