ACK: [PATCH 0/1][SRU][OEM-5.10/H/U] Fix CS8409 crack sound on Bullseye

[Tim Gardner]

Acked-by: Tim Gardner <tim.gardner at canonical.com>

Self contained, affects only one specific bit of HW.

On 4/25/21 9:54 PM, You-Sheng Yang wrote:
> BugLink: https://bugs.launchpad.net/bugs/1924997
> 
> [Impact]
> 
> On a few CS8409 installed platforms, there are crack sounds when playing
> audio with output volume set to 100%.
> 
> [Fix]
> 
> The hardware is not capable of generating smooth audio output at the
> maximum volume that codec chip can be configured. A fix proposed to lower
> the maximum output volume using CS8409 equalizer.
> 
> [Test Case]
> 
> Use GNOME Settings / Sound Settings, set volume to 100%, play test
> audio for both right and left channels; set volume back to 70%, and
> repeat the same to compare to differences. While we don't have acoustic
> lab to perform precise measurements, the result was confirmed by
> partner.
> 
> [Where problems could occur]
> 
> This is to add a preconfigured, equalizer driver default values. This
> will introduce non-uniformed frequency response in comparison to that in
> the hardware preset. The net effect observable to general users is a
> lower maximum output volume. For those Hi-Fi users, audio output always
> takes additional calibration via extra software like ALSAEqual and/or
> hardware.
> 
> [Other Info]
> 
> By SRU we skipped a couple of refactoring changes in asound upstream
> tree, so additional changes to the original patch are required to
> backport.
> 
> Stefan Binding (1):
>    UBUNTU: SAUCE: ALSA: hda/cirrus: Use CS8409 Equalizer to fix abnormal
>      sounds on Bullseye
> 
>   sound/pci/hda/patch_cirrus.c | 33 +++++++++++++++++++++++++++++++++
>   1 file changed, 33 insertions(+)
> 

-- 
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Tim Gardner
Canonical, Inc