From: Nicolin Chen <nicoleotsuka@gmail.com>
To: Mark Brown <broonie@kernel.org>
Cc: Arnaud Ferraris <arnaud.ferraris@collabora.com>,
alsa-devel@alsa-project.org, Timur Tabi <timur@kernel.org>,
Xiubo Li <Xiubo.Lee@gmail.com>,
linux-kernel@vger.kernel.org, Takashi Iwai <tiwai@suse.com>,
Liam Girdwood <lgirdwood@gmail.com>,
Rob Herring <robh+dt@kernel.org>,
kernel@collabora.com, Fabio Estevam <festevam@gmail.com>
Subject: Re: [PATCH 0/4] ASoC: fsl_asrc: allow selecting arbitrary clocks
Date: Tue, 14 Jul 2020 13:50:50 -0700 [thread overview]
Message-ID: <20200714205050.GB10501@Asurada-Nvidia> (raw)
In-Reply-To: <20200714202753.GM4900@sirena.org.uk>
Hi Mark,
On Tue, Jul 14, 2020 at 09:27:53PM +0100, Mark Brown wrote:
> On Tue, Jul 14, 2020 at 01:15:45PM -0700, Nicolin Chen wrote:
> > On Tue, Jul 14, 2020 at 06:20:32PM +0200, Arnaud Ferraris wrote:
>
> > > Here's some background about my use case: the i.MX6 board acts as a
> > > Bluetooth proxy between a phone and a headset. It has 2 Bluetooth
> > > modules (one for each connected device), with audio connected to SSI1 &
> > > SSI2. Audio sample rate can be either 8 or 16kHz, and bclk can be either
> > > 512 or 1024kHz, all depending of the capabilities of the headset and phone.
> > > In our case we want SSI2 to be the input clock to the ASRC and SSI1 the
> > > output clock, but there is no way to force that with auto-selection:
> > > both clocks are multiples of both 8k and 16k, so the algorithm will
> > > always select the SSI1 clock.
>
> > Anything wrong with ASRC selecting SSI1 clock for both cases? The
> > driver calculates the divisors based on the given clock rate, so
> > the final internal rate should be the same. If there's a problem,
> > I feel that's a separate bug.
>
> The nominal rate might be the same but if they're in different clock
> domains then the actual rates might be different (hence the desire for
> an ASRC I guess). I can see the system wanting to choose one clock or
> the other on the basis of some system specific property (quality of the
> clock sources, tolerances of the devices involved or something) though
> it's a rather fun edge case configuration :/ .
Thanks for the input. Fox i.MX6, I don't feel it would be that
drastically different though. And both SSI1 and SSI2 can simply
select the same root clock source to avoid that happen.
Yet, in case that we need to support such an edge case, what's
a relatively common practice to allow system select the clock
source now?
next prev parent reply other threads:[~2020-07-14 20:51 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-02 14:22 [PATCH 0/4] ASoC: fsl_asrc: allow selecting arbitrary clocks Arnaud Ferraris
2020-07-02 14:22 ` [PATCH 1/4] dt-bindings: sound: fsl,asrc: add properties to select in/out clocks Arnaud Ferraris
2020-07-02 14:22 ` [PATCH 2/4] ASoC: fsl_asrc: allow using arbitrary input and output clocks Arnaud Ferraris
2020-07-02 14:22 ` [PATCH 3/4] ASoC: fsl_asrc: always use ratio for conversion Arnaud Ferraris
2020-07-02 14:22 ` [PATCH 4/4] ASoC: fsl_asrc: swap input and output clocks in capture mode Arnaud Ferraris
2020-07-02 18:42 ` [PATCH 0/4] ASoC: fsl_asrc: allow selecting arbitrary clocks Nicolin Chen
2020-07-03 9:38 ` Arnaud Ferraris
2020-07-14 16:20 ` Arnaud Ferraris
2020-07-14 20:15 ` Nicolin Chen
2020-07-14 20:27 ` Mark Brown
2020-07-14 20:50 ` Nicolin Chen [this message]
2020-07-15 14:05 ` Mark Brown
2020-07-15 16:18 ` Arnaud Ferraris
2020-07-15 16:22 ` Mark Brown
2020-07-15 16:32 ` Arnaud Ferraris
2020-07-15 20:46 ` Nicolin Chen
2020-07-16 9:54 ` Arnaud Ferraris
2020-07-15 21:03 ` Nicolin Chen
2020-07-16 12:18 ` Mark Brown
2020-07-16 14:26 ` Arnaud Ferraris
2020-07-17 11:16 ` Arnaud Ferraris
2020-07-23 5:46 ` Nicolin Chen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200714205050.GB10501@Asurada-Nvidia \
--to=nicoleotsuka@gmail.com \
--cc=Xiubo.Lee@gmail.com \
--cc=alsa-devel@alsa-project.org \
--cc=arnaud.ferraris@collabora.com \
--cc=broonie@kernel.org \
--cc=festevam@gmail.com \
--cc=kernel@collabora.com \
--cc=lgirdwood@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=robh+dt@kernel.org \
--cc=timur@kernel.org \
--cc=tiwai@suse.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).