From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: [Xen-devel][PATCH v3 0/5] sndif: add explicit back and front synchronization Date: Tue, 20 Mar 2018 21:22:29 +0100 Message-ID: References: <1521444144-12451-1-git-send-email-andr2000@gmail.com> Mime-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by alsa0.perex.cz (Postfix) with ESMTP id B0BCE2672AF for ; Tue, 20 Mar 2018 21:22:31 +0100 (CET) In-Reply-To: <1521444144-12451-1-git-send-email-andr2000@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Oleksandr Andrushchenko Cc: xen-devel@lists.xenproject.org, alsa-devel@alsa-project.org, Oleksandr Andrushchenko , konrad.wilk@oracle.com List-Id: alsa-devel@alsa-project.org On Mon, 19 Mar 2018 08:22:19 +0100, Oleksandr Andrushchenko wrote: > > From: Oleksandr Andrushchenko > > 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. If other people have no concern, let's go ahead with FE/BE stuff. thanks, Takashi