Gen1 Scarlett 18i6 won't recognize XLR and line jack at the same time (Linux)

[publicradio]

I've been using my Focusrite Scarlett 18i6 with this same computer for about a year, with no problem. Recently, I upgraded my Ubuntu version to 24.04 and now I'm finding that when I open reaper and try to use my inputs, it will 'hear' the Mic in (XLR), or the guitar (1/4 jack), but not both. First, I was only getting the mic. Then I tried unplugging the mic and line, turning the Scarlett off and on, then plugging in the line. Now, Reaper can hear the line but not the mic.

It doesn't matter if I swap the two inputs; it still only seems to want to recognize one or the other, but not both.

This problem wasn't happening before, so I don't know if it's a kernel issue or what. I never needed to install a driver for this unit, and I can't run the GUI for it under wine because it's saying it needs some kind of security update which I don't think I can install in wine. I went into Alsamixer and set both input to Hi-Z, and this didn't fix the problem. Any ideas?

[FranklyFlawless]

Sounds like a regression, so some options include either downgrading Ubuntu back to a working version or upgrading your hardware.

[publicradio]

Thanks for the reply. I realized this isn't an XLR vs line issue; input 1 is non-functional no matter what is in it.

I thought maybe this was hardware failure so I fired up Windows in a virtual machine and ran the official Focusrite app on it. From there input 1 is detected just fine. I can also use my pipewire patchbay and connect the inputs to the Scarlett outputs. All the inputs work fine except input 1. Ubuntu/pipewire sees the first input as capture_AUX0, and it doesn't work in Ubuntu, no matter what I stick into it.

I connected another mic to my computer because I noticed the system input was defaulting to 'Scarlett 18i6 USB Multichannel', which made me think the OS was trying to claim the first input. Changing the input here didn't fix the problem, but I'm still wondering if pipewire isn't reserving AUX0 somehow. Please let me know if you have any thoughts.

[FranklyFlawless]

Try using a Live USB of Ubuntu or Debian and see if it is able to correctly detect the hardware.

[publicradio]

That was a good idea. It was the same with the live USB, though: all the inputs worked except capture_AUX0.

[FranklyFlawless]

What exactly was the last working version and codename of Ubuntu you were using before this issue occurred?

[whyterabbyt]

This is the Hardware (Instruments and Effects) forum, not the Computer Setup forum, which is where soundcard issues should be covered.