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From: Clemens Ladisch <clemens@ladisch.de>
To: Patrick Ziegler <patrick.ziegler@fh-kl.de>
Cc: alsa-devel@alsa-project.org
Subject: Re: SoC Atmel SSC stereo problem
Date: Fri, 22 Oct 2010 18:11:57 +0200	[thread overview]
Message-ID: <4CC1B7CD.3030703@ladisch.de> (raw)
In-Reply-To: <4CC1AB01.3020603@fh-kl.de>

Patrick Ziegler wrote:
> I have some trouble with stereo audio through the atmal ssc interface
> based on at91-ssc.c.

(Merged into atmel_ssc_dai.c since about one year ago.)

> Unfortunately left and right channels were swapped periodically.
> 
> In my environment the codec supplies the BLCK and LRC clocks and
> the SSC is configured to transmit one sample on both edges of the LRC clock.
> But I guess the audio frames will always start with a frame of the left channel
> while the LRC clock is in an undefined state.

Indeed.

> How does normally the audio driver detect when a left and when a right channel
> frame should be send and with which it should start ?

The driver cannot do anything about this; the hardware must be told
to start transmitting at the falling edge.

If possible.

Is there a reason why the codec supplies LRC?


Regards,
Clemens

  reply	other threads:[~2010-10-22 16:10 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-22 15:17 SoC Atmel SSC stereo problem Patrick Ziegler
2010-10-22 16:11 ` Clemens Ladisch [this message]
2010-10-22 21:39   ` Patrick Ziegler
2010-10-23  4:10     ` Alex
2010-10-25  9:16       ` Patrick Ziegler

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