[alsa-devel] [PATCH RESEND] xen/sndif: Sync up with the canonical definition in Xen

[Boris Ostrovsky]

On 04/12/2018 01:26 PM, Oleksandr Andrushchenko wrote:
> This is the sync up with the canonical definition of the sound
> protocol in Xen:
>
> 1. Protocol version was referenced in the protocol description,
>    but missed its definition. Fixed by adding a constant
>    for current protocol version.
>
> 2. Some of the request descriptions have "reserved" fields
>    missed: fixed by adding corresponding entries.
>
> 3. Extend the size of the requests and responses to 64 octets.
>    Bump protocol version to 2.
>
> 4. Add explicit back and front synchronization
>    In order to provide explicit synchronization between backend and
>    frontend the following changes are introduced in the protocol:
>     - add new ring buffer for sending asynchronous events from
>       backend to frontend to report number of bytes played by the
>       frontend (XENSND_EVT_CUR_POS)
>     - introduce trigger events for playback control: start/stop/pause/resume
>     - add "req-" prefix to event-channel and ring-ref to unify naming
>       of the Xen event channels for requests and events
>
> 5. Add explicit back and front parameter negotiation
>    In order to provide explicit stream parameter negotiation between
>    backend and frontend the following changes are introduced in the protocol:
>    add XENSND_OP_HW_PARAM_QUERY request to read/update
>    configuration space for the parameters given: request passes
>    desired parameter's intervals/masks and the response to this request
>    returns allowed min/max intervals/masks to be used.
>
> Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko at epam.com>
> Signed-off-by: Oleksandr Grytsov <oleksandr_grytsov at epam.com>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
> Cc: Takashi Iwai <tiwai at suse.de>
> ---

Reviewed-by: Boris Ostrovsky <boris.ostrovsky at oracle.com>