[alsa-devel] [Xen-devel][PATCH v3 0/5] sndif: add explicit back and front synchronization

[Oleksandr Andrushchenko]

On 03/20/2018 10:22 PM, Takashi Iwai wrote:
> On Mon, 19 Mar 2018 08:22:19 +0100,
> Oleksandr Andrushchenko wrote:
>> From: Oleksandr Andrushchenko <oleksandr_andrushchenko at epam.com>
>>
>> Hello, all!
>>
>> In order to provide explicit synchronization between backend and
>> frontend the following changes are introduced in the protocol:
>>   - bump protocol version to 2
>>   - 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
>>   - add XENSND_OP_HW_PARAM_QUERY request to read/update
>>     stream configuration space: request passes desired intervals/formats for
>>     the stream parameters and the response returns allowed intervals and
>>     formats mask that can be used.
>>
>> Changes since v2:
>> 1. Konrad's r-b tag for version patch
>> 2. MAJOR: changed req/resp/evt packet sizes from 32 to 64 octets
>> 3. Reworked XENSND_OP_HW_PARAM_QUERY so it now sends all
>>     parameters at once, allowing to check all the configuration
>>     space.
>> 4. Minor documentation cleanup (added missed "reserved" fields)
>>
>> Changes since v1:
>>
>> 1. Changed protocol version definition from string to integer,
>> so it can easily be used in comparisons.
>> Konrad, I have removed your r-b tag for the reason of this change.
>>
>> 2. 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 parameter given: request passes
>> desired parameter interval (mask) and the response to this request
>> returns min/max interval (mask) for the parameter to be used.
>>
>> Parameters supported by this request/response:
>>   - format mask
>>   - sample rate interval
>>   - number of channels interval
>>   - buffer size, interval, frames
>>   - period size, interval, frames
> I can't judge exactly about the protocol without the actual FE/BE
> implementations, but the change looks good to me, especially if you've
> already tested something.
Thank you, I have tested the changes and need them to start upstreaming
the frontend driver used to test the protocol.
Do you mind if I put your Acked-by (or you prefer Reviewed-by?) tag to 
these patches:

[PATCH v3 4/5] sndif: Add explicit back and front synchronization
[PATCH v3 5/5] sndif: Add explicit back and front parameter negotiation

Please note, that the changes first to be merged into Xen and then I'll 
prepare
the same, but for the kernel
>
> If other people have no concern, let's go ahead with FE/BE stuff.
Konrad, are you ok with the changes?
>
> thanks,
>
> Takashi
Thank you,
Oleksandr