Re: [PATCH V7 v7] virtio: introduce SUSPEND bit in device status

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Sep 24, 2024 at 03:35:57PM +0800, Jason Wang wrote:
> >
> > > And I still don't see why
> > > introducing a single new bit in the status brings any new troubles
> > > compared with the existing reset and other state transitions.
> >
> > reset is not a state.
> 
> Well, I'm not sure I get this. Each value read from status should
> represent a device state.

What makes you say so? status represents driver state, not device state.
In fact, driver writes there and does not double check with the
sole exception of reset.

> And 0 is a valid status which means device
> is resetted:
> 
> """
> The driver SHOULD consider a driver-initiated reset complete when it
> reads device status as 0.
> """

It means all registers have their reset values, but it is
not a special state in that device behaves normally in this
state, it does not need to be handles in any special way.

Contrast with suspend where device does not respond and
must be first resumed.


-- 
MST