Hi, I've just bought a steinberg ur44. It is reported as having worked in an earlier kernel to the 3.18 rt custom/3.19 low latency generic that I am using. The low latency kernel is generic but the realtime is compiled with the alsa quirks as described here:

http://mailman.alsa-project.org/pipermail/alsa-devel/2014-March/074120.html

On plugging it in, the card is recognised by udev but is disconnected after seemingly being set up. The same error seems to be occurring when I start the machine with the card plugged in. There seems to be an ACL error reported in journalctl. I include the appropriate lines from the udevadm and from journalctl

udevadm:

sudo udevadm monitor

monitor will print the received events for: UDEV - the event which udev sends out after rule processing KERNEL - the kernel uevent

KERNEL[2741.779546] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5 (usb) KERNEL[2741.779705] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.0 (usb) KERNEL[2741.781720] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1 (usb) KERNEL[2741.787500] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3 (sound) KERNEL[2741.787611] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/controlC3 (sound) KERNEL[2741.787813] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/pcmC3D0p (sound) KERNEL[2741.787933] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/pcmC3D0c (sound) KERNEL[2741.788073] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/midiC3D0 (sound) KERNEL[2741.788189] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/midi3 (sound) KERNEL[2741.789228] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/dmmidi3 (sound) KERNEL[2741.789294] remove /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/midi3 (sound) KERNEL[2741.789315] remove /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/dmmidi3 (sound) KERNEL[2741.789365] remove /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/midiC3D0 (sound) KERNEL[2741.789418] remove /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/pcmC3D0p (sound) KERNEL[2741.789436] remove /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/pcmC3D0c (sound) KERNEL[2741.789487] remove /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/controlC3 (sound) KERNEL[2741.789503] remove /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3 (sound) KERNEL[2741.789556] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.2 (usb) KERNEL[2741.789577] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.3 (usb) KERNEL[2741.790043] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.4 (usb) UDEV [2741.810128] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5 (usb) UDEV [2741.810172] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.3 (usb) UDEV [2741.810195] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.2 (usb) UDEV [2741.810217] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1 (usb) UDEV [2741.810237] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3 (sound) UDEV [2741.810260] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/pcmC3D0c (sound) UDEV [2741.810279] remove /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/pcmC3D0c (sound) UDEV [2741.810301] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.4 (usb) UDEV [2741.815664] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/pcmC3D0p (sound) UDEV [2741.815903] remove /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/pcmC3D0p (sound) UDEV [2741.820639] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/midi3 (sound) UDEV [2741.821530] remove /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/midi3 (sound) UDEV [2741.823891] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/dmmidi3 (sound) UDEV [2741.823931] remove /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/dmmidi3 (sound) UDEV [2741.826596] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/midiC3D0 (sound) UDEV [2741.827398] remove /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/midiC3D0 (sound) UDEV [2741.837736] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/controlC3 (sound) UDEV [2741.839478] remove /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/controlC3 (sound) UDEV [2741.840171] remove /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3 (sound) UDEV [2742.842156] add /devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.0 (usb)

journactl (on hotplug add):

Apr 06 19:26:09 super-R720 kernel: usb 1-5: USB disconnect, device number 4 Apr 06 19:26:09 super-R720 systemd-udevd[309]: error opening USB device 'descriptors' file Apr 06 19:26:11 super-R720 kernel: usb 1-5: new high-speed USB device number 5 using ehci-pci Apr 06 19:26:12 super-R720 kernel: usb 1-5: New USB device found, idVendor=0499, idProduct=150e Apr 06 19:26:12 super-R720 kernel: usb 1-5: New USB device strings: Mfr=1, Product=2, SerialNumber=0 Apr 06 19:26:12 super-R720 kernel: usb 1-5: Product: Steinberg UR44 Apr 06 19:26:12 super-R720 kernel: usb 1-5: Manufacturer: Yamaha Corporation Apr 06 19:26:12 super-R720 kernel: snd-usb-audio: probe of 1-5:1.1 failed with error -16 Apr 06 19:26:12 super-R720 mtp-probe[3550]: checking bus 1, device 5: "/sys/devices/pci0000:00/0000:00:1a.7/usb1/1-5" Apr 06 19:26:12 super-R720 mtp-probe[3550]: bus: 1, device: 5 was not an MTP device Apr 06 19:26:12 super-R720 systemd-udevd[3547]: error opening ATTR{/sys/devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/controlC3/ Apr 06 19:26:12 super-R720 systemd-udevd[3560]: Failed to apply ACL on /dev/dmmidi3: No such file or directory Apr 06 19:26:12 super-R720 systemd-udevd[3560]: Failed to apply ACL on /dev/dmmidi3: No such file or directory Apr 06 19:26:12 super-R720 systemd-udevd[3559]: Failed to apply ACL on /dev/midi3: No such file or directory Apr 06 19:26:12 super-R720 systemd-udevd[3559]: Failed to apply ACL on /dev/midi3: No such file or directory Apr 06 19:26:12 super-R720 systemd-udevd[3558]: Failed to apply ACL on /dev/snd/midiC3D0: No such file or directory Apr 06 19:26:12 super-R720 systemd-udevd[3558]: Failed to apply ACL on /dev/snd/midiC3D0: No such file or directory Apr 06 19:26:12 super-R720 systemd-udevd[3549]: Failed to apply ACL on /dev/snd/pcmC3D0c: No such file or directory Apr 06 19:26:12 super-R720 systemd-udevd[3549]: Failed to apply ACL on /dev/snd/pcmC3D0c: No such file or directory Apr 06 19:26:12 super-R720 systemd-udevd[3548]: Failed to apply ACL on /dev/snd/pcmC3D0p: No such file or directory Apr 06 19:26:12 super-R720 systemd-udevd[3548]: Failed to apply ACL on /dev/snd/pcmC3D0p: No such file or directory Apr 06 19:26:12 super-R720 systemd-udevd[3547]: Failed to apply ACL on /dev/snd/controlC3: No such file or directory Apr 06 19:26:12 super-R720 systemd-udevd[3547]: Failed to apply ACL on /dev/snd/controlC3: No such file or directory

journalctl -b:

systemd-udevd[416]: error opening ATTR{/sys/devices/pci0000:00/0000:00:1a.7/usb1/1-5/1-5:1.1/sound/card3/controlC3/.

I can compile a kernel reasonably well, and can understand and program in c, c++, but am not well versed in lower level usb hardware coding. I'd be grateful for any help, many thanks!

Many thanks