Summary of Kernel Issues with USB Audio

Chuck · February 2, 2025, 6:42pm

What does your /etc/modprobe.d/asl3-snd-usb-audio.conf contain?

Users above seem to be reporting that for RPi 5 you need to set options snd_usb_audio lowlatency=1 instead of 0.

It would be nice to see which setting works on an RPi 4…

EDIT: I’ll assume you are not using an interface with a deadman timer to kill PTT if it hangs.

w5mgm · February 2, 2025, 9:06pm

Chuck, thank you. this seems to have solved my issue.

N8EI · February 2, 2025, 10:08pm

I can assure you that lowlatency=0 is the correct setting for a Pi 3 and a Pi 4. I have both and developed the fix packages and tested on both of them. I need to build a Pi 5 test host if it’s going to behave differently. It’s shouldn’t but possibly is…

Chuck · February 2, 2025, 10:52pm

Cool. I’m awaiting audio hardware for my 5.

I assume Takahashi did his fixes on x86_64?

W7VXS · February 2, 2025, 11:32pm

I experienced exactly the same behavior as w7mgm. Wasn’t getting stutter problem until I performed the upgrade last night on my Pi 5. Then got stuttered audio. Seems the upgrade didn’t give me the right Asterisk version for the “fix”. Here’s what I got:
│ OS Kernel : 6.6.74+rpt-rpi-2712
│ Asterisk : 20.11.0+asl3-3.2.0-2.deb12
I changed to: options snd_usb_audio_lowlatency=1
This seems to have fixed my system for now at least. Thanks!

N8EI · February 3, 2025, 12:13am

So it seems like Raspberry Pi 5s have different behavior.

jamesev01 · February 3, 2025, 9:00am

Thank you for taking time to look into this.

6.6.74 and the ASL3 package update were installed together during the same apt upgrade.
No Hotfixes have been installed, only published system updates via apt.
My CM108 is plugged into one of the black (USB2) ports.

zr6tm · February 3, 2025, 8:29pm

Worked 100% Chuick - same issue on a PI5, but all sorted after I updated lowlatency=1.
ZR6TM
73

N8EI · February 4, 2025, 12:39am

Packge asl3-3.7.1-1.deb12 will now set lowlatency=1 for Pi 5 platforms.

n8lbv · February 4, 2025, 5:53am

Ran all the steps and detailed at :

Did not see any obvious problems or errors.
Reboot.

Still showing a -28 kernel.
Is this normal and what I should still be seeing for now?

uname -a

Linux ASL3 6.1.0-28-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.119-1 (2024-11-22) x86_64 GNU/Linux

OS : Debian GNU/Linux 12 (bookworm)
│ OS Kernel : 6.1.0-28-amd64
│
│ Asterisk : 20.11.0+asl3-3.2.0-2.deb12
│ ASL [app_rpt] : 3.2.0
│
│ Installed ASL packages :
│
│ Package Version
│ ============================== ==============================
│ allmon3 1.4.2-1.deb12
│ asl3 3.7.1-1.deb
│ asl3-asterisk 2:20.11.0+asl3-3.2.0-2.deb12
│ asl3-asterisk-config 2:20.11.0+asl3-3.2.0-2.deb12
│ asl3-asterisk-modules 2:20.11.0+asl3-3.2.0-2.deb12
│ asl3-menu 1.11-1.deb12

N8EI · February 4, 2025, 2:31pm

What’s apt-mark showhold report?

n8lbv · February 4, 2025, 5:15pm

“nuthin”.
root@ASL3:~# apt-mark showhold
root@ASL3:~#

~# apt update
Hit:1 Index of /debian bookworm InRelease
Get:2 Index of /debian bookworm-updates InRelease [55.4 kB]
Hit:3 Index of /public/ bookworm InRelease
Hit:4 Index of /debian-security bookworm-security InRelease
Fetched 55.4 kB in 0s (115 kB/s)
Reading package lists… Done
Building dependency tree… Done
Reading state information… Done
All packages are up to date.

N8EI · February 4, 2025, 5:19pm

What’s the output of dpkg -l | grep 'linux-image'?

n8lbv · February 5, 2025, 12:18am

ii linux-image-6.1.0-22-amd64 6.1.94-1 amd64 Linux 6.1 for 64-bit PCs (signed)
ii linux-image-6.1.0-23-amd64 6.1.99-1 amd64 Linux 6.1 for 64-bit PCs (signed)
ii linux-image-6.1.0-26-amd64 6.1.112-1 amd64 Linux 6.1 for 64-bit PCs (signed)
ii linux-image-6.1.0-27-amd64 6.1.115-1 amd64 Linux 6.1 for 64-bit PCs (signed)
ii linux-image-6.1.0-28-amd64 6.1.119-1 amd64 Linux 6.1 for 64-bit PCs (signed)
rc linux-image-6.1.0-29-amd64 6.1.123-1 amd64 Linux 6.1 for 64-bit PCs (signed)
rc linux-image-6.1.0-30-amd64 6.1.124-1 amd64 Linux 6.1 for 64-bit PCs (signed)
rc linux-image-amd64 6.1.124-1 amd64 Linux for 64-bit PCs (meta-package)

N8EI · February 5, 2025, 1:19am

Somehow you uninstalled the metapackage. Do apt install linux-image-amd64 linux-headers-amd64

n8lbv · February 5, 2025, 5:20am

Did that as advised.
Now have:
uname -a
Linux ASL3 6.1.0-30-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.124-1 (2025-01-12) x86_64 GNU/Linux

N8EI · February 5, 2025, 12:55pm

This is the latest kernel.

W6WNG · February 8, 2025, 11:56pm

For a Pi5B system, after completing apt update and apt upgrade - what should be the out put of “/sbin/asterisk -V” ? (No previous hotfixes applied.)

I’m getting:
Asterisk 20.11.0+asl3-3.2.0-2.deb12
… is that correct ?

Also the content of /etc/modprobe.d/asl3-snd-usb-audio.conf is:
options snd_usb_audio lowlatency=1

Best,
Gerry.
W6WNG

Chuck · February 9, 2025, 4:31am

That’s the current version. The lowlatency setting is also correct for Rpi 5.

w6nij · February 13, 2025, 1:01pm

So I’m an Debian X86_64 person that successfully applied the hotfix. I finally got around to applying the suggested upgrade and had the following results:

w6nij@Node622144:~$ sudo apt update && apt upgrade -y
Hit:1 Index of /debian bookworm InRelease
Hit:2 Index of /debian-security bookworm-security InRelease
Hit:3 Index of /debian bookworm-updates InRelease
Hit:4 Index of /public/ bookworm InRelease
Reading package lists… Done
Building dependency tree… Done
Reading state information… Done
12 packages can be upgraded. Run ‘apt list --upgradable’ to see them.
E: Could not open lock file /var/lib/dpkg/lock-frontend - open (13: Permission denied)
E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), are you root?
w6nij@Node622144:~$

Any ideas on what might be the issue?

Thank you.

Tom