linux-kernel - Re: [PATCH] i2c: core: Fix atomic xfer check for non-preempt config

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Date: Thu, 4 Jan 2024 10:33:24 +0100
From: Tor Vic <torvic9@...lbox.org>
To: Benjamin Bara <bbara93@...il.com>, Wolfram Sang <wsa@...nel.org>,
 Lee Jones <lee@...nel.org>, Dmitry Osipenko <dmitry.osipenko@...labora.com>
Cc: peterz@...radead.org, mwalle@...nel.org,
 Erhard Furtner <erhard_f@...lbox.org>, linux-i2c@...r.kernel.org,
 linux-kernel@...r.kernel.org, Benjamin Bara <benjamin.bara@...data.com>,
 stable@...r.kernel.org
Subject: Re: [PATCH] i2c: core: Fix atomic xfer check for non-preempt config



On 1/4/24 09:17, Benjamin Bara wrote:
> From: Benjamin Bara <benjamin.bara@...data.com>
> 
> Since commit aa49c90894d0 ("i2c: core: Run atomic i2c xfer when
> !preemptible"), the whole reboot/power off sequence on non-preempt kernels
> is using atomic i2c xfer, as !preemptible() always results to 1.
> 
> During device_shutdown(), the i2c might be used a lot and not all busses
> have implemented an atomic xfer handler. This results in a lot of
> avoidable noise, like:
> 
> [   12.687169] No atomic I2C transfer handler for 'i2c-0'
> [   12.692313] WARNING: CPU: 6 PID: 275 at drivers/i2c/i2c-core.h:40 i2c_smbus_xfer+0x100/0x118
> ...
> 
> Fix this by allowing non-atomic xfer when the interrupts are enabled, as
> it was before.
> 
> Fixes: aa49c90894d0 ("i2c: core: Run atomic i2c xfer when !preemptible")
> Cc: stable@...r.kernel.org # v5.2+
> Signed-off-by: Benjamin Bara <benjamin.bara@...data.com>

On x86_64 and 6.7-rc8 with voluntary preemption:

Tested-by: Tor Vic <torvic9@...lbox.org>

Thanks for the fix!

> 
> Best regards,