Re: [PATCH 1/3] ASoC: es8316: Increment max value for ALC Capture Target Volume control

From: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
To: Mark Brown <broonie@kernel.org>
Cc: "Rob Herring" <robh+dt@kernel.org>,
	"Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
	"Conor Dooley" <conor+dt@kernel.org>,
	"Heiko Stuebner" <heiko@sntech.de>,
	"Liam Girdwood" <lgirdwood@gmail.com>,
	"Jaroslav Kysela" <perex@perex.cz>,
	"Takashi Iwai" <tiwai@suse.com>,
	"Zhu Ning" <zhuning0077@gmail.com>,
	"Pierre-Louis Bossart" <pierre-louis.bossart@linux.intel.com>,
	"Charles Keepax" <ckeepax@opensource.cirrus.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	"David Yang" <yangxiaohua@everest-semi.com>,
	"Daniel Drake" <drake@endlessm.com>,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
	alsa-devel@alsa-project.org, kernel@collabora.com
Subject: Re: [PATCH 1/3] ASoC: es8316: Increment max value for ALC Capture Target Volume control
Date: Fri, 26 May 2023 21:11:49 +0300	[thread overview]
Message-ID: <3c6b67a4-4892-0057-3dfc-65ed6c7ebc37@collabora.com> (raw)
In-Reply-To: <01fd1a9f-56c7-4864-bb2b-8b004284c8cc@sirena.org.uk>

On 5/24/23 16:59, Mark Brown wrote:
> On Wed, May 24, 2023 at 04:49:37PM +0300, Cristian Ciocaltea wrote:
>> On 5/24/23 13:30, Mark Brown wrote:
> 
>>> Presumably you can check the effects of changing the value?  It seems
>>> plausible that what's written in the code might be accurate and the
>>> higher values might actually change the gain but it'd be better to
>>> check.
> 
>> I haven't noticed a (measurable) change in gain when switching between
>> 10 and 11, but my testing equipment is also not that great. Will try to
>> improve the tests accuracy.
> 
> I'd expect it should be really obvious with a scope if you've got one?
> Testing with something consistent like a sine wave (eg, from
> speaker-test) should also make a 1.5dB difference noticable enough to
> check if there's at least a volume change by ear even if you can't
> specifically quantify it.

Luckily arecord & aplay provide VU meter support (via -V,
--vumeter=TYPE'), so I could easily verify this without using any
additional tools:

 Volume  |  VU meter
---------+----------
-6.0 dB  |  30-31 %
-4.5 dB  |  35-36 %
-3.0 dB  |  42-43 %
-1.5 dB  |  50-51 %
-0.0 dB  |  50-51 %

So it seems the specs are correct, and the problem is the hardware default.

Is there a better approach to handle this than extending the volume range?

Regards,
Cristian

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