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From: Caleb Crome <caleb@crome.org>
To: Fabio Estevam <festevam@gmail.com>
Cc: "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
	Arnaud Mouiche <arnaud.mouiche@invoxia.com>,
	Timur Tabi <timur@tabi.org>,
	Nicolin Chen <nicoleotsuka@gmail.com>,
	Mark Brown <broonie@kernel.org>,
	max.krummenacher@toradex.com,
	Fabio Estevam <fabio.estevam@nxp.com>,
	kernel@pengutronix.de
Subject: Re: [PATCH v2] ASoC: fsl_ssi: Fix channel swap on playback start
Date: Mon, 3 Apr 2017 13:50:01 -0700	[thread overview]
Message-ID: <CAG5mAdzw3__AopSZ37sHh0Q7HSJ+6Z_PDU6vNbgDo6utrB_vJw@mail.gmail.com> (raw)
In-Reply-To: <CAG5mAdyg9jbNcGi6kNLf5s1wk7HkchM5-MjVVJNuATU07HtrUQ@mail.gmail.com>

On Mon, Apr 3, 2017 at 1:32 PM, Caleb Crome <caleb@crome.org> wrote:
> On Sat, Apr 1, 2017 at 7:48 AM, Fabio Estevam <festevam@gmail.com> wrote:
>>
>> From: Fabio Estevam <fabio.estevam@nxp.com>
>>
>> Commit f8fdf5375e2005f2 ("ASoC: fsl-ssi: add SSIEN errata work around")
>> implemented  the workaround for the following erratum found on i.MX35
>> errata document:
>>
>> ENGcm06222: SSI:Transmission does not take place in bit length early
>> frame sync configuration
>>
>> and also for ENGcm06222 from the same document.
>>
>> However it has been only applied for AC97 mode. Apply it to I2S mode
>> as well so that it can fix audio channel swap during playback start.
>>
>> The channel swap can be noticed in about 10% of the times an audio track
>> starts.
>>
>> With the recommended workaround in place no more channel swap
>> happened after running audio start/stop sequence in more than
>> 2000 times.
>>
>> Tested on a mx6dl-wandboard.
>>
>> Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
>> ---
>> Changes since v1:
>> - Do not impact  61fcf10a0ee44763e0 ("ASoC: fsl_ssi: Fix channel slipping in
>> Playback at startup")
>>
>>  sound/soc/fsl/fsl_ssi.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
>> index 17f92b8..549b2a5 100644
>> --- a/sound/soc/fsl/fsl_ssi.c
>> +++ b/sound/soc/fsl/fsl_ssi.c
>> @@ -575,7 +575,9 @@ static void fsl_ssi_config(struct fsl_ssi_private *ssi_private, bool enable,
>>                                         "Timeout waiting TX FIFO filling\n");
>>                         }
>>                 }
>> -               regmap_update_bits(regs, CCSR_SSI_SCR, vals->scr, vals->scr);
>> +               regmap_update_bits(regs, CCSR_SSI_SCR,
>> +                       CCSR_SSI_SCR_SSIEN | CCSR_SSI_SCR_TE | CCSR_SSI_SCR_RE,
>> +                       CCSR_SSI_SCR_SSIEN | CCSR_SSI_SCR_TE | CCSR_SSI_SCR_RE);
>>         }
>>  }
>>
>> --
>> 2.7.4
>>
>
> This patch definitely breaks the i.mx6 channel alignment.  In fact it
> breaks it so that the channels are never aligned properly.
>
> My test setup is as follows:
> * Get vanilla kernel, tag v4.11-rc5
> * apply a couple patches to allow AUD4 on the wandboard external
> connectors (and disable internal audio)

FYI, for anybody that wants to test for themselves, I just posted the
patches for the wandboard here.

https://github.com/ccrome/linux-caleb-dev/wiki

Now that the SSI patches are in the mainline kernel, these 2 simple
patches should make testing the i.mx6 ssi pretty much trivial for
anybody.

-Caleb

  reply	other threads:[~2017-04-03 20:50 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-01 14:48 Fabio Estevam
2017-04-01 15:13 ` Arnaud Mouiche
2017-04-01 16:03   ` Fabio Estevam
2017-04-03  8:19 ` Max Krummenacher
2017-04-03 20:32 ` Caleb Crome
2017-04-03 20:50   ` Caleb Crome [this message]
2017-04-03 21:53   ` Fabio Estevam
2017-04-03 22:05     ` Arnaud Mouiche
2017-04-03 22:20       ` Nicolin Chen
2017-04-03 23:22     ` Caleb Crome
2017-04-03 23:40       ` Fabio Estevam
2017-04-03 23:42         ` Caleb Crome
2017-04-04  8:59           ` Arnaud Mouiche
2017-04-04  9:03             ` Arnaud Mouiche
2017-04-04 11:38             ` Fabio Estevam
2017-04-04 17:12               ` Fabio Estevam
2017-04-04 20:09                 ` Arnaud Mouiche
2017-04-04 20:28                   ` Fabio Estevam
2017-04-05  7:54                     ` Arnaud Mouiche
2017-04-05 13:43                       ` Fabio Estevam
2017-04-05 14:04                       ` Max Krummenacher
2017-04-03 22:08   ` Nicolin Chen
2017-04-03 23:31     ` Caleb Crome
2017-04-03 23:55       ` Nicolin Chen
2017-04-04  0:07         ` Timur Tabi
2017-04-04  0:39         ` Caleb Crome
2017-04-04  1:25           ` Nicolin Chen
2017-04-03 22:36 ` Nicolin Chen
2017-04-03 22:54   ` Fabio Estevam
2017-04-04  0:08     ` Nicolin Chen

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