Re: [PATCH RESEND v2] virtio-input: add multi-touch support

[Vasyl Vavrychuk]

On 09.12.20 10:28, Michael S. Tsirkin wrote:
> On Tue, Dec 08, 2020 at 11:01:50PM +0200, Vasyl Vavrychuk wrote:
> > From: Mathias Crombez <mathias.crombez@xxxxxxxxxxxx>
> > Cc: stable@xxxxxxxxxxxxxxx
>
> I don't believe this is appropriate for stable, looks like
> a new feature to me.

Agree, removed.

> > +config VIRTIO_INPUT_MULTITOUCH_SLOTS
> > +     depends on VIRTIO_INPUT
> > +     int "Number of multitouch slots"
> > +     range 0 64
> > +     default 10
> > +     help
> > +      Define the number of multitouch slots used. Default to 10.
> > +      This parameter is unused if there is no multitouch capability.
> > +
> > +      0 will disable the feature.
> > +
>
> Most people won't be using this config so the defaults matter. So why 10? 10 fingers?
>
> And where does 64 come from?

I have sent v3 version where number of slots it obtained from the host.

> > +     if (is_mt)
> > +             input_mt_init_slots(vi->idev,
> > +                                 CONFIG_VIRTIO_INPUT_MULTITOUCH_SLOTS,
> > +                                 INPUT_MT_DIRECT);
>
>
> Do we need the number in config space maybe? And maybe with a feature
> bit so host can find out whether guest supports MT?

I think it is not applicable in v3 which I sent, because number of slots 
is commit from the host. So, now host controls whether guest support MT.