From: Jie Deng <jie.deng@intel.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Wolfram Sang <wsa@kernel.org>,
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
Date: Fri, 2 Jul 2021 15:15:18 +0800 [thread overview]
Message-ID: <bdea419c-b450-f6b1-fff3-7df077b2abfc@intel.com> (raw)
In-Reply-To: <20210702065625.qielhnfyrlvrtrkk@vireshk-i7>
On 2021/7/2 14:56, Viresh Kumar wrote:
> On 02-07-21, 14:52, Jie Deng wrote:
>> This is not efficient. If adding the ith request to the queue fails, we can
>> still send
>>
>> the requests before it.
> Not really. Normally the requests which are sent together by clients, are linked
> together, like a state machine. So if the first one is sent, but not the second
> one, then there is not going to be any meaningful result of that.
>
> The i2c core doesn't club requests together from different clients in a single
> i2c_transfer() call. So you must assume i2c_transfer(), irrespective of the
> number of underlying messages in it, as atomic. If you fail, the client is going
> to retry everything again or assume it failed completely.
Then what is the need to design this interface as "return the number of
messages successfully
processed, or a negative value on error". Just return success or fail is
enough.
Here, we didn't break the contract with the interface "master_xfer", so
if there is a problem then
the contract may be the problem.
WARNING: multiple messages have this Message-ID (diff)
From: Jie Deng <jie.deng@intel.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: yu1.wang@intel.com, arnd@arndb.de, mst@redhat.com,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org,
Wolfram Sang <wsa@kernel.org>,
linux-i2c@vger.kernel.org, stefanha@redhat.com,
shuo.a.liu@intel.com, andriy.shevchenko@linux.intel.com,
conghui.chen@intel.com
Subject: Re: [PATCH v11] i2c: virtio: add a virtio i2c frontend driver
Date: Fri, 2 Jul 2021 15:15:18 +0800 [thread overview]
Message-ID: <bdea419c-b450-f6b1-fff3-7df077b2abfc@intel.com> (raw)
In-Reply-To: <20210702065625.qielhnfyrlvrtrkk@vireshk-i7>
On 2021/7/2 14:56, Viresh Kumar wrote:
> On 02-07-21, 14:52, Jie Deng wrote:
>> This is not efficient. If adding the ith request to the queue fails, we can
>> still send
>>
>> the requests before it.
> Not really. Normally the requests which are sent together by clients, are linked
> together, like a state machine. So if the first one is sent, but not the second
> one, then there is not going to be any meaningful result of that.
>
> The i2c core doesn't club requests together from different clients in a single
> i2c_transfer() call. So you must assume i2c_transfer(), irrespective of the
> number of underlying messages in it, as atomic. If you fail, the client is going
> to retry everything again or assume it failed completely.
Then what is the need to design this interface as "return the number of
messages successfully
processed, or a negative value on error". Just return success or fail is
enough.
Here, we didn't break the contract with the interface "master_xfer", so
if there is a problem then
the contract may be the problem.
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
next prev parent reply other threads:[~2021-07-02 7:15 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-01 3:24 [PATCH v11] i2c: virtio: add a virtio i2c frontend driver Jie Deng
2021-07-01 3:24 ` Jie Deng
2021-07-01 4:04 ` Viresh Kumar
2021-07-01 4:04 ` Viresh Kumar
2021-07-01 6:10 ` Jie Deng
2021-07-01 6:10 ` Jie Deng
2021-07-01 6:18 ` Viresh Kumar
2021-07-01 6:18 ` Viresh Kumar
2021-07-02 3:36 ` Jie Deng
2021-07-02 3:36 ` Jie Deng
2021-07-02 4:56 ` Viresh Kumar
2021-07-02 4:56 ` Viresh Kumar
2021-07-01 19:24 ` Wolfram Sang
2021-07-02 4:55 ` Viresh Kumar
2021-07-02 4:55 ` Viresh Kumar
2021-07-02 6:22 ` Wolfram Sang
2021-07-02 6:52 ` Jie Deng
2021-07-02 6:52 ` Jie Deng
2021-07-02 6:56 ` Viresh Kumar
2021-07-02 6:56 ` Viresh Kumar
2021-07-02 7:11 ` Wolfram Sang
2021-07-02 7:15 ` Jie Deng [this message]
2021-07-02 7:15 ` Jie Deng
2021-07-02 7:21 ` Viresh Kumar
2021-07-02 7:21 ` Viresh Kumar
2021-07-02 7:36 ` Wolfram Sang
2021-07-01 8:50 ` kernel test robot
2021-07-01 8:50 ` kernel test robot
2021-07-01 8:50 ` kernel test robot
2021-07-01 10:00 ` kernel test robot
2021-07-01 10:00 ` kernel test robot
2021-07-01 10:00 ` kernel test robot
2021-07-02 3:12 ` Jie Deng
2021-07-02 3:12 ` Jie Deng
2021-07-02 3:12 ` Jie Deng
2021-07-02 6:38 ` [kbuild-all] " Rong Chen
2021-07-02 6:38 ` Rong Chen
2021-07-01 10:45 ` Andy Shevchenko
2021-07-01 10:45 ` Andy Shevchenko
2021-07-02 1:05 ` Jie Deng
2021-07-02 1:05 ` Jie Deng
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