[alsa-devel] [PATCH 0/2] ASoC: TWL4030: DAPM restructuring and Headset pop-attenuation fix

Aggarwal, Anuj anuj.aggarwal at ti.com
Mon May 18 17:28:52 CEST 2009

> -----Original Message-----
> From: Mark Brown [mailto:broonie at opensource.wolfsonmicro.com]
> Sent: Monday, May 18, 2009 6:39 PM
> To: Peter Ujfalusi
> Cc: alsa-devel at alsa-project.org; sakoman at gmail.com; Aggarwal, Anuj;
> getarunks at gmail.com
> Subject: Re: [alsa-devel] [PATCH 0/2] ASoC: TWL4030: DAPM restructuring
> and Headset pop-attenuation fix
> On Mon, May 18, 2009 at 04:02:03PM +0300, Peter Ujfalusi wrote:
> > The following series aims to fix the Headset power on/off pop noise
> problems.
> Looks OK but given all the to and fro here I'd rather wait for some
> testing to make sure it works well on other system.s
[Aggarwal, Anuj] I tried this on OMAP3 EVM. Ramp delay values 0-3 produces minor glitches in the beginning & end, value 4 gave me the best result so far on my EVM, I will try with some other EVMs as well before finalizing it. 5 and others produce a beep in the beginning and end.
Just one question, is there any side-effect of choosing a large ramp delay? For e.g. in my case, it could be 437ms (19.2MHz clock).
> > I needed to move the APGA control from SND_SOC_DAPM_PGA to be
> handled with
> > _MIXER. Than adding a PGA to the headset outputs results correct power
> > sequences.
> TBH it sounds like this is actually a mixer anyway - typically mixers do
> have some gain controls associated with them, the sort of PGA DAPM means
> is more an output stage driver.  Typically these have much more control
> of the gain and only one input and output.

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