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Re: [alsa-devel] [PATCH v5 7/9] ASoC: bt-sco: extend rate and add a general compatible string

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  Re: [alsa-devel] [PATCH v5 7/9] ASoC: bt-sco: extend rate and add a  general compatible string Mark Brown <broonie@kernel.org> - 2016-06-30 14:20 +0200
    Re: [alsa-devel] [PATCH v5 7/9] ASoC: bt-sco: extend rate and add a  general compatible string Garlic Tseng <garlic.tseng@mediatek.com> - 2016-06-30 15:00 +0200
      Re: [alsa-devel] [PATCH v5 7/9] ASoC: bt-sco: extend rate and add a  general compatible string Garlic Tseng <garlic.tseng@mediatek.com> - 2016-07-01 05:00 +0200
        Re: [alsa-devel] [PATCH v5 7/9] ASoC: bt-sco: extend rate and add a  general compatible string Mark Brown <broonie@kernel.org> - 2016-07-01 18:20 +0200
          Re: [alsa-devel] [PATCH v5 7/9] ASoC: bt-sco: extend rate and add a  general compatible string Chen-Yu Tsai <wens@csie.org> - 2016-07-02 11:20 +0200
            Re: [alsa-devel] [PATCH v5 7/9] ASoC: bt-sco: extend rate and add a  general compatible string Garlic Tseng <garlic.tseng@mediatek.com> - 2016-07-04 04:00 +0200

#1434492 — Re: [alsa-devel] [PATCH v5 7/9] ASoC: bt-sco: extend rate and add a general compatible string

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On Fri, Jun 17, 2016 at 03:43:58PM +0800, Garlic Tseng wrote:
> Add supports for 16k (wideband BT) and add a general compatible
> string "linux,bt-sco"

This will claim that we support 16k on existing systems which we clearly
don't.  It also seems unwise to advertise multiple rates when we've no
way to configure the rates...  how does the BT controller figure out
what the sample rate is?

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#1434531

On Wed, 2016-06-29 at 20:15 +0100, Mark Brown wrote:
> On Fri, Jun 17, 2016 at 03:43:58PM +0800, Garlic Tseng wrote:
> > Add supports for 16k (wideband BT) and add a general compatible
> > string "linux,bt-sco"
> 
> This will claim that we support 16k on existing systems which we clearly
> don't.  It also seems unwise to advertise multiple rates when we've no
> way to configure the rates...  how does the BT controller figure out
> what the sample rate is?

The codec driver is a dummy driver for bt device and actually do
nothing. The user-space will control both bt part and alsa part (at
least in mt2701 platform). Yes the sound/soc/codecs/bt-sco.c was only
support 8k and was already there before the patch, but I think it might
be ok to extend it to 16k without any side effect.

If you worry about some potential risk (I don't see any) maybe we have
to develop another dummy bt-sco codec driver which support both 8k and
16k?

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#1434985

On Thu, 2016-06-30 at 20:55 +0800, Garlic Tseng wrote:
> On Wed, 2016-06-29 at 20:15 +0100, Mark Brown wrote:
> > On Fri, Jun 17, 2016 at 03:43:58PM +0800, Garlic Tseng wrote:
> > > Add supports for 16k (wideband BT) and add a general compatible
> > > string "linux,bt-sco"
> > 
> > This will claim that we support 16k on existing systems which we clearly
> > don't.  It also seems unwise to advertise multiple rates when we've no
> > way to configure the rates...  how does the BT controller figure out
> > what the sample rate is?
> 
> The codec driver is a dummy driver for bt device and actually do
> nothing. The user-space will control both bt part and alsa part (at
> least in mt2701 platform). Yes the sound/soc/codecs/bt-sco.c was only
> support 8k and was already there before the patch, but I think it might
> be ok to extend it to 16k without any side effect.
> 
> If you worry about some potential risk (I don't see any) maybe we have
> to develop another dummy bt-sco codec driver which support both 8k and
> 16k?

Ah! If someone whose bluetooth modules only support 8k use the driver,
they might be broken, right? Maybe we can add another snd_soc_dai_driver
which can support both 8k and 16k.
(Actually I found the issue is discussed before
http://mailman.alsa-project.org/pipermail/alsa-devel/2014-November/084687.html )

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#1435484

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On Fri, Jul 01, 2016 at 10:49:46AM +0800, Garlic Tseng wrote:
> On Thu, 2016-06-30 at 20:55 +0800, Garlic Tseng wrote:

> > If you worry about some potential risk (I don't see any) maybe we have
> > to develop another dummy bt-sco codec driver which support both 8k and
> > 16k?

> Ah! If someone whose bluetooth modules only support 8k use the driver,
> they might be broken, right? Maybe we can add another snd_soc_dai_driver
> which can support both 8k and 16k.
> (Actually I found the issue is discussed before
> http://mailman.alsa-project.org/pipermail/alsa-devel/2014-November/084687.html )

Yes, that'd be fine - it could be the same driver and register different
parameters depending on config/compatible.

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#1435756

Hi,

On Sat, Jul 2, 2016 at 12:11 AM, Mark Brown <broonie@kernel.org> wrote:
> On Fri, Jul 01, 2016 at 10:49:46AM +0800, Garlic Tseng wrote:
>> On Thu, 2016-06-30 at 20:55 +0800, Garlic Tseng wrote:
>
>> > If you worry about some potential risk (I don't see any) maybe we have
>> > to develop another dummy bt-sco codec driver which support both 8k and
>> > 16k?
>
>> Ah! If someone whose bluetooth modules only support 8k use the driver,
>> they might be broken, right? Maybe we can add another snd_soc_dai_driver
>> which can support both 8k and 16k.
>> (Actually I found the issue is discussed before
>> http://mailman.alsa-project.org/pipermail/alsa-devel/2014-November/084687.html )
>
> Yes, that'd be fine - it could be the same driver and register different
> parameters depending on config/compatible.

Could we also make this driver directly configurable from Kconfig,
and not just selected by platforms (currently Samsung) or by building
all coddecs?

Thanks
ChenYu

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#1436113

On Sat, 2016-07-02 at 17:05 +0800, Chen-Yu Tsai wrote:

Hi,

> Could we also make this driver directly configurable from Kconfig,
> and not just selected by platforms (currently Samsung) or by building
> all coddecs?
> 
> Thanks
> ChenYu

I'll add configure prompt for SND_SOC_BT_SCO in next patchset.
Thanks for comment.

Garlic

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