From: Johan Hovold <johan@kernel.org>
To: Johan Hovold <johan+linaro@kernel.org>
Cc: Mark Brown <broonie@kernel.org>,
Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
Banajit Goswami <bgoswami@quicinc.com>,
Liam Girdwood <lgirdwood@gmail.com>,
Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
alsa-devel@alsa-project.org, linux-sound@vger.kernel.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH v4 2/4] ASoC: qcom: sc8280xp: limit speaker volumes
Date: Fri, 19 Jan 2024 16:26:59 +0100 [thread overview]
Message-ID: <ZaqUw-9XulJGKH7v@hovoldconsulting.com> (raw)
In-Reply-To: <20240119112420.7446-3-johan+linaro@kernel.org>
On Fri, Jan 19, 2024 at 12:24:18PM +0100, Johan Hovold wrote:
> The UCM configuration for the Lenovo ThinkPad X13s has up until now
> been setting the speaker PA volume to the minimum -3 dB when enabling
> the speakers, but this does not prevent the user from increasing the
> volume further.
>
> Limit the digital gain and PA volumes to a combined -3 dB in the machine
> driver to reduce the risk of speaker damage until we have active speaker
> protection in place (or higher safe levels have been established).
>
> Note that the PA volume limit cannot be set lower than 0 dB or
> PulseAudio gets confused when the first 16 levels all map to -3 dB.
I tracked the down the root cause for this, which appears to be a bug
(feature) in pulseaudio that causes it to reject the dB range if the
maximum is negative:
https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/merge_requests/447
This happened to work with v3 which limited the PA volume to the single
lowest setting, but would similarly break if anyone wants to set a -1.5
dB limit.
Johan
next prev parent reply other threads:[~2024-01-19 15:26 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-19 11:24 [PATCH v4 0/4] ASoC: qcom: volume fixes and codec cleanups Johan Hovold
2024-01-19 11:24 ` [PATCH v4 1/4] ASoC: codecs: wsa883x: fix PA volume control Johan Hovold
2024-01-19 11:24 ` [PATCH v4 2/4] ASoC: qcom: sc8280xp: limit speaker volumes Johan Hovold
2024-01-19 15:26 ` Johan Hovold [this message]
2024-01-22 0:03 ` Mark Brown
2024-01-22 7:41 ` Johan Hovold
2024-01-22 16:05 ` Mark Brown
2024-01-22 17:29 ` Johan Hovold
2024-01-22 18:06 ` Mark Brown
2024-01-22 18:21 ` Johan Hovold
2024-01-19 11:24 ` [PATCH v4 3/4] ASoC: codecs: lpass-wsa-macro: fix compander volume hack Johan Hovold
2024-01-19 11:24 ` [PATCH v4 4/4] ASoC: codecs: wcd9335: drop unused gain hack remnant Johan Hovold
2024-01-22 21:54 ` [PATCH v4 0/4] ASoC: qcom: volume fixes and codec cleanups Mark Brown
2024-01-23 7:58 ` Johan Hovold
2024-01-23 13:05 ` Mark Brown
2024-01-23 13:30 ` Johan Hovold
2024-01-23 13:57 ` Mark Brown
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