Problems after switching from Ubuntu Studio 24.04 to 26.04

Support and Help
,
1

Ubuntu Version:
Ubuntu Studio 26.04

Desktop Environment (if applicable):
KDE Plasma

Problem Description:

Hello Good People!,

I recently did a fresh install of Ubuntu Studio 26.04 because I thought I may as well move with the times and check the new OS out.

However, I have had some problems:

When I use my DAW with Focusrite Scarlett interface it all works well. However, if I put the laptop in sleep mode, there is no audio when I wake the laptop up and want to continue. Qpwgraph looks the same upon waking and the DAW itself behaves as if there is audio playing (meters showing sound). However, there is no audio coming through my headphones. If I restart the DAW it works again. Or if I go into Pulse Audio Volume Control and toggle, for example, the fall back device on and off it works again but I would prefer it to just keep working upon waking as it did when I was using Ubuntu Studio 24.04

Also, when I was following a guide on optimising Ubuntu Studio 26.04 for audio production. I noticed that the following command brought up a ‘permission denied’ message:

cat /sys/kernel/debug/sched/preempt

Also, when I was trying to see if pipewire was using real time scheduling using this command:

ps -eLo pid,tid,cls,rtprio,comm | grep pipewire

The readout showed 'TS' when, according to the guide, it should have shown FF

This guide is on linuxdj.com

I wonder if the guide is misleading me or I am misunderstanding something.

So I am here asking for some help. I don't really want to go back to 24.04 but I will if I can't resolve/gain an understanding of these issues.

I've tried asking AI for help but I have learned that it's suggestions cannot always be trusted.

Any help much appreciated

Best

Matt Hammond
2

Welcome to Ubuntu Discourse, Matt!

That’s kind of redundant because Ubuntu Studio is already optimized for “Studio” work, hence the name. :wink:
I wonder if it was something in that guide that caused this. One thing that comes to mind is a major upgrade of pipewire, which changed the configuration layout, so things that worked in 24.04 won’t in 26.04 unless one migrates the config manually to the new layout.

That’s because of kernel lockdown, which is enabled automatically, when Secure Boot is enabled. You can check the kernel command line:

cat /proc/cmdline

If there is no preempt parameter, it’s the default for your kernel:

grep PREEMPT /boot/config*

I think, it’s the latter, because it’s the same for me. The important thing is that your user is a member of the pipewire group, which is configured to allow realtime scheduling via rtkit-daemon. You can dig deeper into individual threads, but that shouldn’t be necessary.

“Ai” isn’t. :wink:

3

Hi there,

Ok, thanks very much. I know that Ubuntu Studio comes ready for audio production but I thought I could tweak it a bit. I am disappointed by the article on linuxdj.com; the author wrote with such an air of authority. I will just re-install the OS and see if the lack of audio problem is still there. On 24.04 if I pulled out the USB cable to the interface then the audio would just come out of the laptop speakers with no interruption. Now if I do it, the stream gets paused. I don’t know if this is relevant. I just notice what is different in 26.04. Thanks for your kind help.

Best

Matt

4

Can you post the full link, so we can get an idea, what is proposed?

That’s how it’s supposed to work, yes.

Yes, it is very relevant.

I think you should use vanilla Ubuntu Studio and see if it works properly, before “optimizing”. All too often that makes things worse.

5

I just reinstalled Ubuntu Studio 26.04 and didn’t tweak anything
I still get the same problem. When I use my DAW and then put the laptop to sleep (I previously chose not to lock the screen when waking from sleep) it doesn’t play audio when I wake it up and try to play some audio in the DAW. It looks like it is (meters registering sounds in DAW) but no actual sound coming from headphones anymore.

Also if I am watching a video with the USB interface plugged in and then pull the cable out, the audio pauses..It didn’t do this with 24.04

Maybe it is some kind of bug. Maybe I should just go back to 24.04? I was happy with that and it will get security updates until 2029. I await your response.

Thanks again for your kind assistance. I really appreciate it.

The link to the article is here: https://www.linuxdj.com/notes/ubuntu-studio-26-04-lts-pro-audio-setup-2026/

Multiple commands here do not work. Maybe it is just some AI slop?

Best

Matt Hammond

6

It could be a bug, yes. If going back to 24.04 is acceptable, by all means, do it. :wink:
But this could also be an opportunity to help fix it. Maybe wait and see if others have some ideas, because right now I am not sure where to look.

7

Yeah, I hope I can help fix it. I will wait a bit to see if there is some fix. I think it might be something to do with Pulse Audio Volume Control..If I go in there and toggle the ‘fallback’ options on and off..then the problem is fixed..until the next reboot

8

PA Volume Control is just a frontend to PulseAudio/PipeWire. So the ‘fallback’ is not enabled by default? There should always be one device that serves as fallback. What happens if you leave it ‘on’?

Since it’s a USB device, there might be some USB issue involved. I’m thinking of power management.

9

I’ve noticed that the ‘fallback’ device is the one that is in use at the time. If I plug in the USB interface then PAVU shows that as the fall back device. If I unplug it then it shows the laptop speakers are the fallback device. I can change it but it reverts back upon reboot. Yeah it could be some auto-suspend thing maybe. I dunno. I am more of a musician than linux guru.

10

It seems unlikely that this is a DAW-specific issue, but just out of curiousity which one are you using?

I’ve seen Ardour disconnect the Master bus from the audio hardware when awaking from sleep, from time to time.

I’m on Ubuntu Studio 24.04.4 LTS and won’t consider updating until the 26.04.1 release comes out in August. So I owe you a big THANK YOU for finding stuff like this, it’s really important that it get reported and solved!

11

Hi there,

I am using Tracktion Waveform 13.5; same as I used on 24.04

Yeah, I think I am going to go back to 24.04 and hope this gets figured out by August

I tried adding the stop USB autosuspend text to the GRUB file but that didn’t work.

Thanks for chipping in with your take on this

Best

Matt

12

I noticed that the USB audio can also fail when I unplug the interface when listening to a stream and then plug it back in
I notice that I get a notification when I plug it in and unplug it which didn’t happen on 24.04 so maybe it is connected with the tweaks to Plasma. Also the audio is paused when unplugging the USB interface
Also when I put the laptop into sleep mode, the USB interface no longer displays the green usb symbol
I don’t think this happened on 24.04

13

For some reason, there is also a ‘speech dispatcher dummy’ involved in the audio chain when I look at qpwgraph
Don’t know if that is meant to be there


14

Have you tried the new PipeWire config applet?

By your description, I’m thinking that your audio gets rerouted to a dummy sink, when suspending – may be related to session locking – and it somehow fails to reconnect to your device. But without some more info, we are pretty much left to speculate.

If it’s a bug, it won’t get fixed unless someone reports it.

15

Ubuntu Studio lead here.

It’s definitely AI-written. There is some AI-written material that is OK, but this is not that. It’s someone looking to make a quick buck off of clicks.

I have some major objections to these “what to do after installing x” articles because, if you know of something that people should be doing, maybe contribute to the development (which we make it super easy to do) by just being in conversation with us? We can change the defaults and add features or remove features, but only if people tell us during the development cycle and before feature freeze.

Now to your issue: I have reason to believe this is a hardware issue, but there might be a way to mitigate it. Focusrite Scarlett interfaces tend to be problematic as Focusrite only releases their software for Windows, and they’re not “class-compliant” devices. Just as an FYI, in my 32 years of doing audio, 8 of which has been leading Ubuntu Studio, I have never recommended Focusrite Scarlett devices, even though they’re considered the “industry standard”. I actually recommend less-expensive devices that are class-compliant and own three of them: Behringer UM22, UHD404HD, and the XR-18. They use Midas preamps, so they sound every bit as good as more expensive ones, and the UHD404HD can even do 192Khz sample rates.

But, I digress. I suspect what’s happening is that when the computer goes to sleep it is switching off its USB ports and then, when it wakes up, the Scarlett is just having difficulty. I’m not sure if there’s a setting it needs, but I highly recommend trying the alsa-scarlett-gui which, if I could, I would include in Ubuntu Studio if it weren’t for a major license issue. which is already in the repositories and can be installed via sudo apt install alsa-scarelett-gui. I’ll make sure this is part of Ubuntu Studio 26.10 and onward.

There’s also a piece of this in that the kernel is newer in 26.04 than 24.04 and might have a newer power saving setting that it switching it off. Sadly, I don’t have any way of guiding you through that, but it usually requires finding the device ID, going to somewhere in /sys/devices/pci* or something and finding the power control, which is likely “auto”, and doing a echo "on" | sudo tee control to that device. This is entirely complicated, but I had to do something similar to my internal sound card to keep it from constantly shutting-off my SPDIF optical out. Unfortunately, I cannot guide you through this as it’s way too complicated.

Anyhow, I hope this information is somewhat helpful. I think the problem is a power-saving related thing, and I hope you can find it or someone can guide you through it.

2 Likes
16

Hmm. That could be it! I saw a ‘dummy speech dispatcher’ in qpwgraph after it happened. I had chosen ‘no locking screen’ after wake up from sleep.

What exact info do you need? Some logs? Please tell me. I would love to get this fixed

17

This just gave me a thought. Maybe the powertop TUI can help here. To make sure it’s installed, run this:

sudo apt install powertop

Then run:

sudo powertop

And hit Tab until you are on the “Tunables” tab. Look for lines starting with “Good”, which is actually bad for our intents and purposes:

   Good          Enable Audio codec power management
   Good          Autosuspend for USB device xHCI Host Controller [usb2]
   Good          Autosuspend for USB device xHCI Host Controller [usb4]
   Good          Autosuspend for USB device Integrated Camera [SunplusIT Inc]
   Good          Autosuspend for USB device xHCI Host Controller [usb1]
   Good          Autosuspend for USB device xHCI Host Controller [usb3]

This is an excerpt from my machine. You can toggle the settings by navigating to the appropriate line(s) and pressing Enter, so it says “Bad”. That also shows a line with the corresponding command at the top, e.g.:

>> echo 'on' > '/sys/bus/pci/devices/0000:00:18.2/power/control';

just like @eeickmeyer suggested. This may come in handy later. For now just toggle everything that even smells like audio or USB to “Bad”. These changes are temporary and will not survive a reboot.

Then do a suspend/resume cycle and see if that changes anything. If so, you can try to narrow it down to (an) individual device(s). Once found, I can walk you through how to make that setting stick on reboot, @matt-hammond.

18

That’s going to need a sudo tee otherwise it will fail.

Also, edit to my post above. alsa-scarlett-gui is already in Ubuntu, install with

sudo apt install alsa-scarelett-gui

Seems as though someone with better reasoning than myself decided the license incompatibility wasn’t a problem! It will be in Ubuntu Studio 26.10 and onward by default.

1 Like
19

Not when you run it in a root shell, which sudo powertop effectively is. :wink:
I was aiming to find the correct sysfs files to then use sysfsutils, so the echo is of minor interest.

But it looks like, I might not have to:

:clap:

20

Hey thanks for giving me all that info. Very interesting. I would have bought a different interface had I known. However, it worked fine on 24.04 without the ‘alsa-scarlett-gui’

I will try installing it though. and report back.

It’s a shame you can’t give me a guide on editing that power file. I will ask elsewhere about it.

Thanks again