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

[Oleksandr Andrushchenko <andr2000@gmail.com>]

On 06/07/2018 06:47 PM, Konrad Rzeszutek Wilk wrote:
> On Thu, Jun 07, 2018 at 04:40:48PM +0300, Oleksandr Andrushchenko wrote:
>> 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@epam.com>
>>>>
>>>> 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@epam.com>
>>>> ---
>>>>    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.
> Please do and feel free to add
>
> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>
> on it.
>
> Also pls CC Juergen so he can release-ack it.
Thank you
>>>> + *
>>>> + *      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
>>>>


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