[alsa-devel] [PATCH 1/2 v2] ASoC: nau8825: non-clock jack detection for power saving at standby

[Mark Brown]

On Fri, May 20, 2016 at 11:12:39AM +0800, John Hsu wrote:
> On 5/19/2016 1:05 AM, Mark Brown wrote:

> > > [PATCH] ASoC: nau8825: apply BIQ to reduce recording signal DC offset

> > This is hard to review since it's quite complex and doing things that
> > look like they might be using general purpose parts of the chip for
> > specialist purposes.

> We find there is a DC offset issue when recording. For the issue, it
> needs a HPF in ADC to reduce the offset, but no such hardware circuit.
> Thus, the driver configures the biquard filter as HPF when headset
> connected. It is a must setup for the codec. This patch sets the
> coefficients A1, A2, B0, B1, and B3 in the biquad filter to make the
> HPF funciton.

I understand what it's doing but obviously a biquad filter isn't
specialized for this function...
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