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Date:   Fri, 20 Jul 2018 13:05:49 +0200
From:   Wolfram Sang <wsa@the-dreams.de>
To:     Arnd Bergmann <arnd@arndb.de>
Cc:     Peter Rosin <peda@axentia.se>,
        Boris Brezillon <boris.brezillon@bootlin.com>,
        linux-i2c@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
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        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
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        Bartosz Folta <bfolta@cadence.com>,
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Subject: Re: [PATCH v6 00/10] Add the I3C subsystem
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> * What I understand from reading i2c-demux-pinctrl.c, a slave device
>   will only ever be observable from one master at a time, when you
>   switch over, all children get removed on one master and added to
>   the other one, to be probed again by their respective drivers.

Yes. The very first versions of the demuxer tried to do it in a
hot-swapping like fashion but then I switched over because of...

> it definitely opens up questions in what happens to e.g. the sysfs
> representation, lock order, and power management that I'd rather
> not have to think about.

... this! There are dragons, I can tell you :)

> * The other thing we definitely have to support for i3c is to deal with
>    handing over control of the bus between the i3c master owned
>    by Linux, and other masters that are /not/ owned by the same
>    Linux instance. This is the part that the spec discusses in much
>    detail, with the intention of temporarily giving up control of the
>    bus to let another master do its thing on a shared slave without
>    user interaction.

I can't comment about this one.


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