[alsa-devel] [PATCH 1/3] ASoC: TWL4030: Enable voice filters for voice sidetone

[Peter Ujfalusi]

On Friday 19 June 2009 12:58:08 ext Mark Brown wrote:
> On Fri, Jun 19, 2009 at 03:23:41AM -0500, Lopez Cruz, Misael wrote:
> > Digital voice loopback (sidetone) requires voice filters
> > to be enabled: VTXL, VTXR, VRX.
>
> Is it possible to handle this by inserting DAPM widgets for these
> filters into the bypass paths and letting DAPM power them up? 

I think for the Voice interface this is feasible.

> I'm also wondering if with the new bias level management stuff which keeps
> the codec in BIAS_ON while any DAPM widgets are powered some of the bypass
> mode stuff can be removed or simplified?

I have been wondering about the same, but in the HiFi path it is not that 
simple. Most probably it is possible to add DAPM widget for the Audio Filter 
L1/R1 (which is at the moment always enabled), but for the L2/R2 it is not 
that simple.
Simplifying the twl4030_mute function should be possible at this point, I 
think, by moving those output mutes as DAPM_PGA_E widgets on the paths. This 
is in my to-do list... Although I have to check that such a change should not 
cause any 'clicks' on the outputs.

>
> I'm OK with the change if Peter acks it, I've not got detailed knowledge
> of the TWL4030.

I think this patch is not good. See my comment on the patch.

-- 
Péter