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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jie Deng <jie.deng@intel.com>
Cc: "Viresh Kumar" <viresh.kumar@linaro.org>,
	"Wolfram Sang" <wsa@kernel.org>,
	"Jason Wang" <jasowang@redhat.com>,
	"Vincent Guittot" <vincent.guittot@linaro.org>,
	"Arnd Bergmann" <arnd@kernel.org>,
	stratos-dev@op-lists.linaro.org,
	"Alex Bennée" <alex.bennee@linaro.org>,
	cohuck@redhat.com,
	"Vincent Whitchurch" <vincent.whitchurch@axis.com>,
	linux-i2c@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org, conghui.chen@intel.com
Subject: Re: [PATCH] i2c: virtio: Add support for zero-length requests
Date: Fri, 22 Oct 2021 05:03:36 -0400	[thread overview]
Message-ID: <20211022050222-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <0adf1c36-a00b-f16f-e631-439148c4f956@intel.com>

On Fri, Oct 22, 2021 at 02:51:10PM +0800, Jie Deng wrote:
> 
> On 2021/10/21 17:47, Viresh Kumar wrote:
> > The virtio specification received a new mandatory feature
> > (VIRTIO_I2C_F_ZERO_LENGTH_REQUEST) for zero length requests. Fail if the
> > feature isn't offered by the device.
> > 
> > For each read-request, set the VIRTIO_I2C_FLAGS_M_RD flag, as required
> > by the VIRTIO_I2C_F_ZERO_LENGTH_REQUEST feature.
> > 
> > This allows us to support zero length requests, like SMBUS Quick, where
> > the buffer need not be sent anymore.
> > 
> > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> > ---
> > Hi Wolfram,
> > 
> > Please do not apply this until the spec changes [1] are merged, sending it early
> > to get review done. I will ping you later once the spec is merged.
> > 
> > [1] https://lists.oasis-open.org/archives/virtio-dev/202110/msg00109.html
> > 
> >   drivers/i2c/busses/i2c-virtio.c | 56 ++++++++++++++++++---------------
> >   include/uapi/linux/virtio_i2c.h |  6 ++++
> >   2 files changed, 36 insertions(+), 26 deletions(-)
> > 
> 
> Acked-by: Jie Deng<jie.deng@intel.com>  once the spec is merged.


There's supposed to be space before < btw. and one puts # before any
comments this way tools can process the ack automatically:

Acked-by: Jie Deng<jie.deng@intel.com> # once the spec is merged.

> 
> 
> > +	if (!virtio_has_feature(vdev, VIRTIO_I2C_F_ZERO_LENGTH_REQUEST)) {
> > +		dev_err(&vdev->dev, "Zero-length request feature is mandatory\n");
> > +		return -EINVAL;
> 
> 
> It might be better to return -EOPNOTSUPP ?
> 


WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jie Deng <jie.deng@intel.com>
Cc: Arnd Bergmann <arnd@kernel.org>,
	Vincent Whitchurch <vincent.whitchurch@axis.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	cohuck@redhat.com, linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	Wolfram Sang <wsa@kernel.org>,
	conghui.chen@intel.com, linux-i2c@vger.kernel.org,
	stratos-dev@op-lists.linaro.org
Subject: Re: [PATCH] i2c: virtio: Add support for zero-length requests
Date: Fri, 22 Oct 2021 05:03:36 -0400	[thread overview]
Message-ID: <20211022050222-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <0adf1c36-a00b-f16f-e631-439148c4f956@intel.com>

On Fri, Oct 22, 2021 at 02:51:10PM +0800, Jie Deng wrote:
> 
> On 2021/10/21 17:47, Viresh Kumar wrote:
> > The virtio specification received a new mandatory feature
> > (VIRTIO_I2C_F_ZERO_LENGTH_REQUEST) for zero length requests. Fail if the
> > feature isn't offered by the device.
> > 
> > For each read-request, set the VIRTIO_I2C_FLAGS_M_RD flag, as required
> > by the VIRTIO_I2C_F_ZERO_LENGTH_REQUEST feature.
> > 
> > This allows us to support zero length requests, like SMBUS Quick, where
> > the buffer need not be sent anymore.
> > 
> > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> > ---
> > Hi Wolfram,
> > 
> > Please do not apply this until the spec changes [1] are merged, sending it early
> > to get review done. I will ping you later once the spec is merged.
> > 
> > [1] https://lists.oasis-open.org/archives/virtio-dev/202110/msg00109.html
> > 
> >   drivers/i2c/busses/i2c-virtio.c | 56 ++++++++++++++++++---------------
> >   include/uapi/linux/virtio_i2c.h |  6 ++++
> >   2 files changed, 36 insertions(+), 26 deletions(-)
> > 
> 
> Acked-by: Jie Deng<jie.deng@intel.com>  once the spec is merged.


There's supposed to be space before < btw. and one puts # before any
comments this way tools can process the ack automatically:

Acked-by: Jie Deng<jie.deng@intel.com> # once the spec is merged.

> 
> 
> > +	if (!virtio_has_feature(vdev, VIRTIO_I2C_F_ZERO_LENGTH_REQUEST)) {
> > +		dev_err(&vdev->dev, "Zero-length request feature is mandatory\n");
> > +		return -EINVAL;
> 
> 
> It might be better to return -EOPNOTSUPP ?
> 

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  parent reply	other threads:[~2021-10-22  9:03 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-21  9:47 [PATCH] i2c: virtio: Add support for zero-length requests Viresh Kumar
2021-10-21  9:47 ` Viresh Kumar
2021-10-22  6:51 ` Jie Deng
2021-10-22  6:51   ` Jie Deng
2021-10-22  6:58   ` Viresh Kumar
2021-10-22  6:58     ` Viresh Kumar
2021-10-22  7:08     ` Arnd Bergmann
2021-10-22  9:03   ` Michael S. Tsirkin [this message]
2021-10-22  9:03     ` Michael S. Tsirkin
2021-10-26 11:14 ` Viresh Kumar
2021-10-26 11:14   ` Viresh Kumar

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