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Date:   Fri, 2 Jul 2021 08:22:13 +0200
From:   Wolfram Sang <wsa@kernel.org>
To:     Viresh Kumar <viresh.kumar@linaro.org>
Cc:     Jie Deng <jie.deng@intel.com>, linux-i2c@vger.kernel.org,
        virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org, mst@redhat.com, arnd@arndb.de,
        jasowang@redhat.com, andriy.shevchenko@linux.intel.com,
        yu1.wang@intel.com, shuo.a.liu@intel.com, conghui.chen@intel.com,
        stefanha@redhat.com
Subject: Re: [PATCH v11] i2c: virtio: add a virtio i2c frontend driver
Message-ID: <YN6wlXw2KhALAyS3@kunai>
Mail-Followup-To: Wolfram Sang <wsa@kernel.org>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Jie Deng <jie.deng@intel.com>, linux-i2c@vger.kernel.org,
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        jasowang@redhat.com, andriy.shevchenko@linux.intel.com,
        yu1.wang@intel.com, shuo.a.liu@intel.com, conghui.chen@intel.com,
        stefanha@redhat.com
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> > > Wolfram, what's expected here ? Shouldn't all message transfer or
> > > none?
> >=20
> > Well, on a physical bus, it can simply happen that after message 3 of 5,
> > the bus is stalled, so we need to bail out.
>=20
> Right, and in that case the transfer will have any meaning left? I believ=
e it
> needs to be fully retried as the requests may have been dependent on each=
 other.

The client driver handles the case. I'd assume most will bail out of the
calling function and at some higher level it will be retried.

> > Of course, it can later happen on the physical bus of the host, though,
> > that the bus is stalled after message 3 of 5, and I2C_RDWR will bail
> > out.
>=20
> Basically we fail as soon as we know something is not right, correct?

Yes.


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