Re: [PATCH 0/4] ALSA: usb-audio: Demote the severity of sticky GET_CUR

[Faaris Ansari <faaris.ansari@gmail.com>]

Hi there,

I am continuing to have a bug across the latest 7.2 kernels, as well as 
6.18 and 6.12 LTS branches concerning hardware volume control on my 
Audient EVO4, that I think is related to this issue - would appreciate 
some guidance if not.

Specifically, when changing volume via the knob on the front of the 
device, everything works perfectly, but when modifying volume through 
pwvucontrol or wpctl the volume drastically lowers. As far as I can 
understand, pipewire is resorting to a software mixer for the device for 
some reason, whilst also actively modifying the hardware volume at the 
same time - is this what should occur with "sticky mixers"?

prior to kernels 7.2 (tested 7.1.13) the volume control works perfectly 
via wpctl.

I attempted to add a quirk flag to snd_usb_audio to work around the 
issue without success:

```

sudo modprobe snd_usb_audio quirk_flags=2708:0006:mixer_get_cur_broken

```


I also tried applying these patches to add extra mixer controls to my 
EVO4: https://lore.kernel.org/lkml/20260919151840.24371-1-arc@gmx.li/

This worked fine after I modified the UCM conf for the device to follow 
the new (correct) naming scheme for the master volume, but the volume 
problem was still occuring.


is this problem I'm having related to these sticky mixers?


I originally reported this to wireplumber thinking it was an issue 
there, more information is provided at the link below:

https://gitlab.freedesktop.org/pipewire/wireplumber/-/work_items/1022


As I've never reported anything upstream to the kernel before, I'd 
appreciate extra guidance where necessary. Would love to get this solved 
as its making all volume control on my system unusable, and the change 
which has caused it has also been pushed to LTS kernels, leaving me with 
no working kernel besides reverting to the now EOL 7.1 series.


Faaris