[alsa-devel] TWL4030 Line In/Out Loopback issue

Péter Ujfalusi peter.ujfalusi at ti.com
Mon Aug 8 10:56:36 CEST 2011


On Monday 08 August 2011 02:27:45 Almohanad Fayez wrote:
>  I'verealized that there is a loopback dependency between the
> audioinput/output dependency with the 2.6.38 kernel running on a gumstix
> overo and also using the 2.6.35 kernel running on the Beaglenboard.

I can not recall seeing such an issue.

> You can replicate this issue by plugging some music into the Line injack and
> then fire up alsamixer.  Then you would need to modify theDAC2 Dig level,
> the one on the right no the left.  As you lower thevolume you'll hear your
> music input decreasing and as you increase itthe music level would
> increase.  If you lower it enough you can captureaudio from the input jack
> without hearing it out of your speaker butthe bad thing is that also
> controls your speaker output so if you tryto play some sound out of
> gumstix/beagleboard you won't be able to do because youneed to increase
> your DAC2 Dig level in alsamixer ... it's a catch22!!  I couldn't find any
> solutions readily.

Have you checked the state of the Left/Right Digital Loopback? Is it set to 0?

> I am running a console-only Angstrom image on both boards.  I've used the
> Beagleboard's line in/out capabilities with no issues using the 2.6.29
> kernel in the past so is there an update in the TWL4030 ALSA driver that I
> should take into account?  thanks

Could you post the content of the
file to see what's going on?


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