From: Wolfram Sang <wsa@the-dreams.de>
To: Stephen Warren <swarren@wwwdotorg.org>
Cc: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
Stephen Warren <swarren@nvidia.com>,
Phil Carmody <phil.carmody@partner.samsung.com>,
stable@vger.kernel.org
Subject: Re: [PATCH] i2c: Re-instate body of i2c_parent_is_i2c_adapter()
Date: Tue, 14 Jan 2014 17:12:54 +0100 [thread overview]
Message-ID: <20140114161254.GA6442@katana> (raw)
In-Reply-To: <1389648544-4201-1-git-send-email-swarren@wwwdotorg.org>
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On Mon, Jan 13, 2014 at 02:29:04PM -0700, Stephen Warren wrote:
> From: Stephen Warren <swarren@nvidia.com>
>
> The body of i2c_parent_is_i2c_adapter() is currently guarded by
> CONFIG_I2C_MUX instead.
This paragraph sounds strange to me. I'll update it a little. After that
I'll go looking for a brown paper bag...
> Among potentially other problems, this resulted in i2c_lock_adapter()
> only locking I2C mux child adapters, and not the parent adapter. In
> turn, this could allow inter-mingling of mux child selection and I2C
> transactions, which could result in I2C transactions being directed to
> the wrong I2C bus, and possibly even switching between busses in the
> middle of a transaction.
>
> One concrete issue caused by this bug was corrupted HDMI EDID reads
> during boot on the NVIDIA Tegra Seaboard system, although this only
> became apparent in recent linux-next, when the boot timing was changed
> just enough to trigger the race condition.
>
> Fixes: 3923172b3d70 ("i2c: reduce parent checking to a NOOP in non-I2C_MUX case")
> Cc: Phil Carmody <phil.carmody@partner.samsung.com>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Stephen Warren <swarren@nvidia.com>
Applied to for-current, thanks for catching this one!
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next prev parent reply other threads:[~2014-01-14 16:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-13 21:29 [PATCH] i2c: Re-instate body of i2c_parent_is_i2c_adapter() Stephen Warren
2014-01-14 16:12 ` Wolfram Sang [this message]
2014-01-16 17:25 ` Stephen Warren
[not found] ` <52D8160B.7090205-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
2014-01-16 18:04 ` Wolfram Sang
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