Re: [Xen-devel] [PATCH 2/3] xen/kbdif: Add unique input device identifier

[Oleksandr Andrushchenko <andr2000@xxxxxxxxx>]

On 06/07/2018 04:28 PM, Konrad Rzeszutek Wilk wrote:
> On Wed, May 23, 2018 at 09:19:22AM +0300, Oleksandr Andrushchenko wrote:
> > From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
> >
> > If frontend is configured to expose multiple input device instances
> > then backend may require a way to uniquely identify concrete input
> > device within the frontend. This is useful for use-cases where
> > virtual input device needs to be matched to physical input device.
> > Add XenBus "unique-id" node parameter, so this sort of use-cases can
> > be implemented.
> >
> > Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
> > ---
> >   xen/include/public/io/kbdif.h | 10 ++++++++++
> >   1 file changed, 10 insertions(+)
> >
> > diff --git a/xen/include/public/io/kbdif.h b/xen/include/public/io/kbdif.h
> > index a68da0f1a37f..45e4ff5b0a05 100644
> > --- a/xen/include/public/io/kbdif.h
> > +++ b/xen/include/public/io/kbdif.h
> > @@ -82,6 +82,15 @@
> >    *      for pointer devices should set this to 1. Raw (unscaled) values have
> >    *      a range of [0, 0x7fff].
> >    *
> > + *-----------------------  Device Instance Parameters ------------------------
> > + *
> > + * unique-id
> > + *      Values:         <uint32_t>
> Wouldn't a string be easier? That way you can extend this in the future
> to also have an UUID or so?
Much easier. We were thinking about that as well, but sndif already has it
as uint32_t. If you are ok to change uniquie-id for sndif to string then 
that
would be much better: UUID as you mention + all protocols have unique-id
consistently defined as string.
sndif's unique-id is not used by the frontend driver and we are about
to start libx/xl support for sound, so I think this is the right time for
such a change.
If you are fine with that then I'll send yet another patch for sndif.
> > + *
> > + *      After device instance initialization it is assigned a unique ID
> > + *      (within the front driver), so every instance of the frontend can be
> > + *      identified by the backend by this ID.
> > + *
> >    *------------------------- Pointer Device Parameters ------------------------
> >    *
> >    * width
> > @@ -204,6 +213,7 @@
> >   #define XENKBD_FIELD_MT_WIDTH          "multi-touch-width"
> >   #define XENKBD_FIELD_MT_HEIGHT         "multi-touch-height"
> >   #define XENKBD_FIELD_MT_NUM_CONTACTS   "multi-touch-num-contacts"
> > +#define XENKBD_FIELD_UNIQUE_ID         "unique-id"
> >   
> >   /* OBSOLETE, not recommended for use */
> >   #define XENKBD_FIELD_RING_REF          "page-ref"
> > --
> > 2.17.0

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel