Re: [virtio-dev] Re: [virtio-comment] [PATCH v4] virtio-i2c: add the device specification

[Jie Deng <jie.deng@intel.com>]

On 2020/11/19 23:55, Paolo Bonzini wrote:
> On 19/11/20 02:41, Jie Deng wrote:
> > > No, the kick is only an advice. The device is allowed to poll on 
> > > the ring and ignore kicks completely, for example.
> > >
> > > Paolo
> > Understood. But I saw your proposal can only group two segments 
> > "write-read".
> > What if we have segments more than two ? for example, 
> > "write-read-read..." or "write-write-write...".
> > Can we use a flag to tag the START/STOP segments so that they can be 
> > grouped into one transaction ?
>
> Grouping of more than two segments is not particularly common, a lot 
> of host devices might not support it (unless they simply do bitbanging).
>
> On the other hand grouping of two segments _is_ common enough that it 
> is probably supported by many host devices, and worth supporting it in 
> virtio-i2c.
>
> You can certainly add an "u32 flags" to the buffer for future 
> extensibility. That's a good idea regardless.
>
> Paolo
Understood... Thank you !