Re: [virtio-dev] [PATCH] Add virtio parameter server device specification

[Cornelia Huck <cohuck@redhat.com>]

On Fri, 7 May 2021 16:06:41 -0700
Hao Chen <chenhaosjtuacm@google.com> wrote:

> > Your client seems to introduce line wraps...  
> 
> Thanks for pointing it out, we will fix it in the following patches.
> 
> > Do these two types need to be handled differently? If I set up a
> > subscription "poll this parameter every n ms", it doesn't really matter
> > why the parameter changes, does it? In any case, it is not under
> > control of the driver, as "actions of the external system" may also
> > change a mutable parameter.  
> 
> The reason we want to handle "MUTABLE" and "CONTNUOUS" differently is,
> the MUTABLE values are not constantly changing, so the device may be able to
> send every updates of it to the driver; while CONTINUOUS values are changing
> frequently (e.g., sensor outputs) and the device should decide how to sample it
> and provide a sample rate range ("min_sample_freq" and "max_sample_freq")

Can you add that explanation to the paragraph? It gives good guidance
when to use which type.

> 
> > s/device-readable// ?  
> 
> If I understand correctly, the driver need to fill the virtqueues no
> matter who is the
> reader, so "device-readable" is necessary here. What do you think?

But isn't the eventq supposed to relay information from the device to
the driver?