Re: [PATCH] ASoC: codecs: wcd938x: fix dB range for HPHL and HPHR

[Johan Hovold <johan@kernel.org>]

On Fri, Jul 07, 2023 at 01:54:31PM +0100, Srinivas Kandagatla wrote:
> On 07/07/2023 08:35, Johan Hovold wrote:
> > On Wed, Jul 05, 2023 at 01:57:23PM +0100, Srinivas Kandagatla wrote:
  
> >>   static const SNDRV_CTL_TLVD_DECLARE_DB_MINMAX(ear_pa_gain, 600, -1800);
> >> -static const SNDRV_CTL_TLVD_DECLARE_DB_MINMAX(line_gain, 600, -3000);
> >> +static const DECLARE_TLV_DB_SCALE(line_gain, -3000, 150, -3000);
> > 
> > This looks wrong, and indeed that forth argument appears to be a mute
> > flag. I guess that one should have been 0 (false) here?
> 
> yes, this should be true instead of a mute dB value.

Ok, so mute is supported. Then that argument can just be changed to "1"
as a cleanup to follow the current convention.

> > Headphone output also appears to be way too loud by default with this
> > patch (alone) applied. Perhaps it's just the default mixer settings need
> > to be updated to match?
> > 
> > It looks like you're inverting the scale above. Perhaps that's intended,
> 
> yes, the highest value corresponds to lowest dB which is why its inverted.

Got it, thanks.

> > but some more details in the commit message as to what was wrong and
> > what you intended to do would have been good.
> 
> HPHR/HPHL Volume control is broken on this codec.
> current UCM uses digital volume control for x13s which needs to be moved 
> to Analog volume control.
> I have this change https://termbin.com/mpp9 in UCM which I plan to send 
> out once I test and fix other paths as well.

With those UCM changes the headphone volume appears to be restored even
if pavucontrol now sets the "base" marker at 80% rather than 20% volume
on the X13s (which is much too loud here).

Audio quality seem fine and I'm not hearing any distortion at 20%
volume as some people were complaining about (even if I haven't really
used the headphones myself before).

Sounds like you had a similar fix for the speaker distortion coming soon
too, looking forward to that one.

Johan