Hi folks, just recently started using Solus but otherwise long time Linux user (Debian, Fedora and mostly Ubuntu).
I've been very successfully DJing with Mixxx, it's an amazing piece of open source software. So I fired it up on Solus 4.0 and it works fine and detects my USB sound card, but fails to find my usb DJ controller, which has been working reliably for years. The system logs state:

Sep 08 20:45:56 ripley pulseaudio[949]: [pulseaudio] module-alsa-card.c: Failed to find a working profile.
Sep 08 20:45:56 ripley pulseaudio[949]: [pulseaudio] module.c: Failed to load module "module-alsa-card" (argument: "device_id="2" name="usb-Evolution_Electronics_Ltd._USB_X-Session-00" card_name="alsa_card.usb-Evolution_Electronics_Ltd._USB_X-Session-00" namereg_fail=false tsched=yes fixed_latency_range=no ignore_dB=no deferred_volume=yes use_ucm=yes card_properties="module-udev-detect.discovered=1""): initialization failed.

I can't understand why Alsa should be having issues with this. Is this an Alsa bug? Or am I missing some packages? I don't have this problem on Ubuntu (using libasound2-plugins 1.1.8). On Solus I'm using alsa-plugins 1.1.9. Anyone have any ideas or should I contact the Alsa devs?

Following up from this, seems like I might need the snd_seq_midi kernel module installed. I'm going to check this and report back. If it's not present, this would be a nice thing to have pre-installed ootb.

8 months later

Hey pierrep, did you ever get your controller working? I have having a similar issue with Mixxx not recognizing my controller (DDJ-SB3) but it being listed upon commands such as aplaymidi -l