Zoom R24 USB multichannel audio interface no longer recognized

I'm new here so my apologies if I'm asking questions at the wrong place. Someone told me this could be a regression in ALSA.
I'm running Fedora and have used a Zoom R24 as a USB multichannel audio interface (8-in/2-out) for many years.
Recently I upgraded to Fedora 42 and now the device is presented as dumb 2-in/2-out USB audio interface.
"pavucontrol" does not present multi-channel profiles for the device.
The command "alsamixer -c 1" (to select the R24) gives "This device does not have any controls.".
"qjackctl" also shows 2-in/2-out channels.
I use the device with "ardour" for multi-channel recording but that no longer works, only 2-in/2-out channels are available.
How can I get the R24 fully functional again?
Thanks,

On 25. 06. 25 15:45, Johan Vromans wrote:
I'm new here so my apologies if I'm asking questions at the wrong place. Someone told me this could be a regression in ALSA.
I'm running Fedora and have used a Zoom R24 as a USB multichannel audio interface (8-in/2-out) for many years.
Recently I upgraded to Fedora 42 and now the device is presented as dumb 2-in/2-out USB audio interface.
"pavucontrol" does not present multi-channel profiles for the device.
The command "alsamixer -c 1" (to select the R24) gives "This device does not have any controls.".
"qjackctl" also shows 2-in/2-out channels.
I use the device with "ardour" for multi-channel recording but that no longer works, only 2-in/2-out channels are available.
How can I get the R24 fully functional again?
Could you show us output from `alsa-info.sh` script ? URL should be enough.
Jaroslav

On Wed, 25 Jun 2025 15:45:17 +0200, Johan Vromans jvromans@squirrel.nl wrote:
Recently I upgraded to Fedora 42 and now the device is presented as dumb 2-in/2-out USB audio interface.
Sorry, false alarm.
The R24 was connected via a KVM/USB switch, and that played tricks. After connecting the R24 directly, or via a decent hub, the problem disappeared and all channels are available again.
Apologies for the disturbance.
participants (2)
-
Jaroslav Kysela
-
Johan Vromans