linux-kernel - Re: [PATCH 07/11] soundwire: intel: Only call sdw stream APIs for the first cpu

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Message-ID: <20200828074544.GM2639@vkoul-mobl>
Date:   Fri, 28 Aug 2020 13:15:44 +0530
From:   Vinod Koul <vkoul@...nel.org>
To:     "Liao, Bard" <bard.liao@...el.com>
Cc:     Bard Liao <yung-chuan.liao@...ux.intel.com>,
        "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "tiwai@...e.de" <tiwai@...e.de>,
        "broonie@...nel.org" <broonie@...nel.org>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "jank@...ence.com" <jank@...ence.com>,
        "srinivas.kandagatla@...aro.org" <srinivas.kandagatla@...aro.org>,
        "rander.wang@...ux.intel.com" <rander.wang@...ux.intel.com>,
        "ranjani.sridharan@...ux.intel.com" 
        <ranjani.sridharan@...ux.intel.com>,
        "hui.wang@...onical.com" <hui.wang@...onical.com>,
        "pierre-louis.bossart@...ux.intel.com" 
        <pierre-louis.bossart@...ux.intel.com>,
        "Kale, Sanyog R" <sanyog.r.kale@...el.com>,
        "Lin, Mengdong" <mengdong.lin@...el.com>
Subject: Re: [PATCH 07/11] soundwire: intel: Only call sdw stream APIs for
 the first cpu_dai

On 28-08-20, 01:47, Liao, Bard wrote:
> > snd_pcm_substream *substream,
> > >  			goto err;
> > >  	}
> > >
> > > -	ret = sdw_prepare_stream(dma->stream);
> > > +	/*
> > > +	 * All cpu dais belong to a stream. To ensure sdw_prepare_stream
> > > +	 * is called once per stream, we should call it only when
> > > +	 * dai = first_cpu_dai.
> > > +	 */
> > > +	if (first_cpu_dai == dai)
> > > +		ret = sdw_prepare_stream(dma->stream);
> > 
> > Hmmm why not use the one place which is unique in the card to call this,
> > hint machine dais are only called once.
> 
> Yes, we can call it in machine driver. But, shouldn't it belong to platform
> level? The point is that if we move the stuff to machine driver, it will
> force people to implement these stuff on their own Intel machine driver.

nothing stops anyone from doing that right! machine driver is another
component so it can be moved there as well

-- 
~Vinod