From: Wolfram Sang <wsa+renesas@sang-engineering.com>
To: Carlos Song <carlos.song@nxp.com>
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
Date: Wed, 14 Jan 2026 12:59:24 +0100 [thread overview]
Message-ID: <aWeFHNiNuHLdhZrO@ninjato> (raw)
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 <carlos.song@nxp.com>
> Reviewed-by: Frank Li <Frank.Li@nxp.com>
Applied to for-current, thanks!
prev parent reply other threads:[~2026-01-14 11:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-21 3:00 [PATCH v3] i2c: imx-lpi2c: change to PIO mode in system-wide suspend/resume progress Carlos Song
2025-11-21 3:20 ` Frank Li
2026-01-14 11:59 ` Wolfram Sang [this message]
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