Arch Linux

shanti

Member

Registered: 2022-04-22

Posts: 3

usb-audio module patch introduces regression since kernels 5.11xx

Hi,

This patch https://lore.kernel.org/all/20210111081 … i@suse.de/
introduces the lock of the sample rate which doesn't follow my configuration of switching the sample rate to a multiple of the audio playing. Moreover it feels that the playing speed isn't accurate (slightly accelerated) when playing an audio file which has a non multiple of the locked sample rate.

Similar bug as https://bugzilla.redhat.com/show_bug.cgi?id=1930199

As an additional information, upgrading from pulseaudio 13 to 15 has the effect of achieving the speakers balance at 100% volume only. If I lower the volume, it kills one side.

My soundcard is a usb Audient id14.

Could you point me to the right place to post the bug if not relevant here, or/and give me instructions how to revert the patch for a recent 5.17x kernel.

Thanks,

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,209

Re: usb-audio module patch introduces regression since kernels 5.11xx

You should be able to enable the implicit_fb sync with the  implicit_fb=1 parameter to the snd_usb_audio module, if I'm reading the constellation correctly here then this might help without needing to change the code

shanti

Member

Registered: 2022-04-22

Posts: 3

Re: usb-audio module patch introduces regression since kernels 5.11xx

Thank you very much, I created /etc/modprobe.d/snd_usb_audio.conf reading

options snd_usb_audio implicit_fb=1 

then rebooting under linux-5-16.15-1

unfortunately it doesn't work.

systool -vm snd_usb_audio returns

implicit_fb         = "Y,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N"

so I modified /etc/modprobe.d/snd_usb_audio.conf into

options snd_usb_audio implicit_fb="Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y"

then systool -vm snd_usb_audio returns

implicit_fb         = "Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y"

but still the issue persists...it seems there is more than implicit-fb involved in that patch.

Last edited by shanti (2022-04-22 15:26:15)

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,209

Re: usb-audio module patch introduces regression since kernels 5.11xx

Also make sure you're on 5.17.4 there have been quite a few changes around this code in the .4 release.

Last edited by V1del (2022-04-22 15:27:09)

shanti

Member

Registered: 2022-04-22

Posts: 3

Re: usb-audio module patch introduces regression since kernels 5.11xx

No luck here, just tried with linux-5.17.4....even updated the soundcard firmware.

The offending patch dates back to linux-5.11, so I wonder if that's rather a policy to use only one sample rate...

As I don't multi stream to my ears, I play one audio file at a time, the audio sink is reset in between each files, so adapting the sample rate was just working great along with the soundcard....hence I feel a regression.