[alsa-devel] [PATCH] ASoC: imx-ssi: Fix mono playback

Fabio Estevam festevam at gmail.com
Tue Aug 7 02:32:10 CEST 2012

Hi Timur,

On Mon, Aug 6, 2012 at 8:33 PM, Tabi Timur-B04825 <B04825 at freescale.com> wrote:
> On Mon, Aug 6, 2012 at 2:58 PM, Fabio Estevam <festevam at gmail.com> wrote:
>> Do you know if mono playback used to work previously in imx-ssi?
> I doubt it.  I don't think the I2S standard allows for mono playback,
> so the SSI would need to send the same sample twice, and I don't see
> any support for that feature in the RM.
> When I wrote fsl_ssi, I couldn't find any way to get mono playback to work.
> BTW, I can't find the original patch in my inbox or the mailing list
> archives.  When was it sent?

I sent the patch from FSL and it was blocked because I am not
subscribed in alsa-devel list from my FSL account.

The original patch I sent was the following and it allowed me to play
a mono track:

>From bc46087110bd48a41f1f7dcb826853349662c766 Mon Sep 17 00:00:00 2001
From: Fabio Estevam <fabio.estevam at freescale.com>
Date: Mon, 6 Aug 2012 16:30:51 -0300
Subject: [PATCH] ASoC: imx-ssi: Fix mono playback

Currently mono playback is played on a faster rate.

Adjust channels_min to 2 channels in order to play it back correctly.

Reported-by: Gaëtan Carlier <gcembed at gmail.com>
Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>
 sound/soc/fsl/imx-ssi.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/sound/soc/fsl/imx-ssi.c b/sound/soc/fsl/imx-ssi.c
index 28dd76c..c42df31 100644
--- a/sound/soc/fsl/imx-ssi.c
+++ b/sound/soc/fsl/imx-ssi.c
@@ -380,7 +380,7 @@ static int imx_ssi_dai_probe(struct snd_soc_dai *dai)
 static struct snd_soc_dai_driver imx_ssi_dai = {
 	.probe = imx_ssi_dai_probe,
 	.playback = {
-		.channels_min = 1,
+		.channels_min = 2,
 		.channels_max = 2,
 		.rates = SNDRV_PCM_RATE_8000_96000,
 		.formats = SNDRV_PCM_FMTBIT_S16_LE,

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