From mboxrd@z Thu Jan 1 00:00:00 1970 From: Charles Keepax Subject: Re: [alsa-devel] [PATCH v2 3/5] ASoC: core: add support to snd_soc_dai_get_sdw_stream() Date: Thu, 10 Oct 2019 12:03:37 +0000 Message-ID: <20191010120337.GB31391@ediswmail.ad.cirrus.com> References: <20190813191827.GI5093@sirena.co.uk> <20190813195804.GL5093@sirena.co.uk> <20190814041142.GU12733@vkoul-mobl.Dlink> <99d35a9d-cbd8-f0da-4701-92ef650afe5a@linux.intel.com> <5e08f822-3507-6c69-5d83-4ce2a9f5c04f@linaro.org> <53bb3105-8e85-a972-fce8-a7911ae4d461@linux.intel.com> <95870089-25da-11ea-19fd-0504daa98994@linaro.org> <2326a155-332e-fda0-b7a2-b48f348e1911@linux.intel.com> <34e4cde8-f2e5-0943-115a-651d86f87c1a@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-path: Content-Disposition: inline In-Reply-To: <34e4cde8-f2e5-0943-115a-651d86f87c1a@linaro.org> Sender: linux-kernel-owner@vger.kernel.org To: Srinivas Kandagatla Cc: Pierre-Louis Bossart , Vinod Koul , Mark Brown , devicetree@vger.kernel.org, alsa-devel@alsa-project.org, bgoswami@codeaurora.org, plai@codeaurora.org, lgirdwood@gmail.com, linux-kernel@vger.kernel.org, robh+dt@kernel.org, spapothi@codeaurora.org List-Id: devicetree@vger.kernel.org On Thu, Oct 10, 2019 at 09:50:22AM +0100, Srinivas Kandagatla wrote: > On 09/10/2019 19:53, Pierre-Louis Bossart wrote: > >On 10/9/19 11:01 AM, Srinivas Kandagatla wrote: > >>On 09/10/2019 15:29, Pierre-Louis Bossart wrote: > >>>On 10/9/19 3:32 AM, Srinivas Kandagatla wrote: > >>>>On 14/08/2019 15:09, Pierre-Louis Bossart wrote: > >>>>>On 8/13/19 11:11 PM, Vinod Koul wrote: > >>>>>>On 13-08-19, 20:58, Mark Brown wrote: > >>>>>>>On Tue, Aug 13, 2019 at 02:38:53PM -0500, Pierre-Louis > >>>>>>>>Indeed. I don't have a full understanding of that > >>>>>>>>part to be honest, nor why > >>>>>>>>we need something SoundWire-specific. We already > >>>>>>>>abused the set_tdm_slot API > >>>>>>>>to store an HDaudio stream, now we have a rather confusing stream > >>>>>>>>information for SoundWire and I have about 3 other > >>>>>>>>'stream' contexts in > >>>>>>>>SOF... I am still doing basic cleanups but this has > >>>>>>>>been on my radar for a > >>>>>>>>while. > >>>>>>> > >>>>>>>There is something to be said for not abusing the TDM > >>>>>>>slot API if it can > >>>>>>>make things clearer by using bus-idiomatic mechanisms, > >>>>>>>but it does mean > >>>>>>>everything needs to know about each individual bus :/ . > >>>>>> > >>>>>>Here ASoC doesn't need to know about sdw bus. As Srini > >>>>>>explained, this > >>>>>>helps in the case for him to get the stream context and > >>>>>>set the stream > >>>>>>context from the machine driver. > >>>>>> > >>>>>>Nothing else is expected to be done from this API. We > >>>>>>already do a set > >>>>>>using snd_soc_dai_set_sdw_stream(). Here we add the > >>>>>>snd_soc_dai_get_sdw_stream() to query > >>>>> > >>>>>I didn't see a call to snd_soc_dai_set_sdw_stream() in Srini's code? > >>>> > >>>> > >>>>There is a snd_soc_dai_get_sdw_stream() to get stream > >>>>context and we add slave streams(amplifier in this case) to > >>>>that context using sdw_stream_add_slave() in machine > >>>>driver[1]. > >>>> > >>>>Without this helper there is no way to link slave streams to > >>>>stream context in non dai based setup like smart speaker > >>>>amplifiers. > >>>> > >>>>Currently this driver is blocked on this patch, If you think > >>>>there are other ways to do this, am happy to try them out. > >>> > >>>So to be clear, you are *not* using snd_soc_dai_set_sdw_stream? > >>Yes, am not using snd_soc_dai_set_sdw_stream(). > > > >It's been a while since this thread started, and I still don't > >quite get the concepts or logic. > > > >First, I don't understand what the problem with "aux" devices is. > >All the SoundWire stuff is based on the concept of DAI, so I guess > >I am > > That is the actual problem! Some aux devices does not have dais. > Usually aux devices are used for things like analog amplifiers that clearly don't have a digital interface, thus it really makes no sense to have a DAI link connecting them. So I guess my question here would be what is the thinking on making the "smart amplifier" dailess? It feels like having a CODEC to CODEC DAI between the CODEC and the AMP would be a more obvious way to connect the two devices and would presumably avoid the issues being discussed around the patch. Thanks, Charles