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Date:   Mon, 27 Apr 2020 09:22:33 +0200
From:   Thierry Reding <thierry.reding@gmail.com>
To:     Sasha Levin <sashal@kernel.org>
Cc:     Jon Hunter <jonathanh@nvidia.com>, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org, Dmitry Osipenko <digetx@gmail.com>,
        Wolfram Sang <wsa@the-dreams.de>, linux-i2c@vger.kernel.org,
        linux-tegra@vger.kernel.org
Subject: Re: [PATCH AUTOSEL 5.6 30/38] i2c: tegra: Better handle case where
 CPU0 is busy for a long time
Message-ID: <20200427072233.GB3451400@ulmo>
References: <20200424122237.9831-1-sashal@kernel.org>
 <20200424122237.9831-30-sashal@kernel.org>
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On Fri, Apr 24, 2020 at 08:22:28AM -0400, Sasha Levin wrote:
> From: Dmitry Osipenko <digetx@gmail.com>
>=20
> [ Upstream commit a900aeac253729411cf33c6cb598c152e9e4137f ]
>=20
> Boot CPU0 always handle I2C interrupt and under some rare circumstances
> (like running KASAN + NFS root) it may stuck in uninterruptible state for
> a significant time. In this case we will get timeout if I2C transfer is
> running on a sibling CPU, despite of IRQ being raised. In order to handle
> this rare condition, the IRQ status needs to be checked after completion
> timeout.
>=20
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
>  drivers/i2c/busses/i2c-tegra.c | 27 +++++++++++++++------------
>  1 file changed, 15 insertions(+), 12 deletions(-)

Hi Sasha,

can you drop this from the v5.6 stable queue please? Jon discovered that
this patch introduces a regression in v5.7, and since we don't have a
good understanding of why this is breaking things I think it'd be best
if we reverted it for v5.7 until we come up with a good fix.

I think the same applies for the other i2c/tegra patch that's 31/38 of
this series.

Thanks,
Thierry

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