I just wanted to say thank you for your work on this, and for sharing it. I thought I was losing my mind with my MOTU 16A and 8A interfaces drifting and nothing I could do would resolve it. This driver saved them on Linux for me.

sudo dkms build motu-avb-usb/1.0

Kernel preparation unnecessary for this kernel. Skipping...

Building module: cleaning build area...(bad exit status: 2) make -j16 KERNELRELEASE=5.4.0-122-generic all KVERSION=5.4.0-122-generic...(bad exit status: 2) Error! Bad return status for module build on kernel: 5.4.0-122-generic (x86_64) Consult /var/lib/dkms/motu-avb-usb/1.0/build/make.log for more information.

also there is no make.log generated

Motu 828es with firmware 1.3.5.+184 Ubuntu 21.10 with kernel 5.13.0-30-lowlatency

Kernel patches in place, mostly configure correctly (I think). Configured the device using the attached script. Buffer size and safety offset in the web UI are set to 'display: none' for some reason so I thought I'd mention that.

I'm pretty sure I have the kernel patched correctly but I'll go back and double check everyhing.

I had audio coming through briefly but it was distorted and coming through on four channels. While I'm messing with all that I see an error I thought I'd share in case it's something important.

[ 3423.927796] usb 3-3: samplerate = 44100, queue_length = 21, midi = 1, vendor = 1
[ 3423.927800] usb 3-3: probing interface 1
[ 3423.927823] usb 3-3: probing interface 2
[ 3423.927831] usb 3-3: probing interface 5
[ 3423.927838] usb 3-3: probing interface 4
[ 3423.927845] usb 3-3: probing interface 6
[ 3423.927851] usb 3-3: probing interface 7
[ 3423.927858] usb 3-3: probing interface 3
[ 3423.927865] usb 3-3: probing interfaces sucessful
[ 3423.927866] usb 3-3: invalid capture endpoint: 0
[ 3423.927934] usbcore: registered new interface driver motu
[ 3423.941632] usbcore: registered new interface driver snd-usb-audio

I added logging to see which endpoint was invalid by adding this line at line 1104 in motu.c

dev_err(&ua->dev->dev, "invalid capture endpoint: %d\n", usb_endpoint_num(epd)); motu-setup.txt

Noticed some bits in my system journal:

Feb 02 02:06:30 skylyn pulseaudio[590]: ALSA woke us up to write new data to the device, but there was actually nothing to write.
Feb 02 02:06:30 skylyn pulseaudio[590]: Most likely this is a bug in the ALSA driver 'motu'. Please report this issue to the ALSA developers.
Feb 02 02:06:30 skylyn pulseaudio[590]: We were woken up with POLLOUT set -- however a subsequent snd_pcm_avail() returned 0 or another value < min_avail.

I thought this was related to the interface sometimes starting up weirdly where it wouldn't lock the sample rate properly, but this appeared to also be logged after i rebooted the interface and tried to play something - it took a couple seconds for the audio to kick in.

Hi,

i've been using the Motu 24Ao for a while now and since the firmware upgrade to 1.3.5+1028 is have distortion and loss of signal when sending audio to the device. I currently use 8 channels from the computer to the device to then mix it to the outputs. It is not clear for me which driver i need and if any of the drivers will work with my device. I've tried the one on the page. It plays audio but only on all channels, i've had an asound.conf to define 4 sources and it used to work with the default linux audio driver. But with this new driver it doesn't seem to work, however it is not clear to me why this doesn't work anymore.

I can provide extra information if needed, i'm not an expert in kernel modules so i don't really know which way is the best way to solve my issues. I think i have the channel drifting issue, the signal seems to play, than start to distort en disappear to somewhat later reappear.

pcm_slave.motu {
  pcm "hw:1,0"
  rate 48000
  channels 8
}

pcm.source1 {
  type plug
  slave.pcm {
    type dmix
    slave motu
    ipc_key 1001
    ipc_perm 0666
    bindings [ 0 1 ]
  }
}

pcm.source2 {
  type plug
  slave.pcm {
    type dmix
    slave motu
    ipc_key 1001
    ipc_perm 0666
    bindings [ 2 3 ]
  }
}

pcm.source3 {
  type plug
  slave.pcm {
    type dmix
    slave motu
    ipc_key 1001
    ipc_perm 0666
    bindings [ 4 5 ]
  }
}

pcm.source4 {
  type plug
  slave.pcm {
    type dmix
    slave motu
    ipc_key 1001
    ipc_perm 0666
    bindings [ 6 7 ]
  }
}

First, thank very much for your work! This is helping me a lot!

However, I still have a problem.

I'm running Debian unstable with the 5.15.0-2-amd64 kernel and I'm using a MOTU AVB 1248. I've followed your instructions and successfully installed the module. lsusb -t shows:

/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/10p, 5000M
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/16p, 480M
    |__ Port 1: Dev 9, If 5, Class=Vendor Specific Class, Driver=motu, 480M
    |__ Port 1: Dev 9, If 3, Class=Vendor Specific Class, Driver=motu, 480M
    |__ Port 1: Dev 9, If 1, Class=Audio, Driver=motu, 480M
    |__ Port 1: Dev 9, If 4, Class=Vendor Specific Class, Driver=motu, 480M
    |__ Port 1: Dev 9, If 2, Class=Audio, Driver=motu, 480M
    |__ Port 1: Dev 9, If 0, Class=Audio, Driver=motu, 480M
    |__ Port 4: Dev 2, If 1, Class=Human Interface Device, Driver=usbhid, 12M
    |__ Port 4: Dev 2, If 2, Class=Human Interface Device, Driver=usbhid, 12M
    |__ Port 4: Dev 2, If 0, Class=Human Interface Device, Driver=usbhid, 12M
    |__ Port 5: Dev 3, If 1, Class=Human Interface Device, Driver=usbhid, 12M
    |__ Port 5: Dev 3, If 2, Class=Human Interface Device, Driver=usbhid, 12M
    |__ Port 5: Dev 3, If 0, Class=Human Interface Device, Driver=usbhid, 12M
    |__ Port 7: Dev 4, If 0, Class=Video, Driver=uvcvideo, 480M
    |__ Port 7: Dev 4, If 1, Class=Video, Driver=uvcvideo, 480M
    |__ Port 12: Dev 6, If 1, Class=Wireless, Driver=btusb, 12M
    |__ Port 12: Dev 6, If 0, Class=Wireless, Driver=btusb, 12M

so everything seem alright.

Still, when I try to play something to the MOTU card, using qjackctl to connect some source to it, I get the following error message in syslog:

spa.alsa: set_hw_params: Cannot allocate memory
pw.node: (alsa_output.usb-MOTU_1248_0001f2fffe000bff-00.playback.0.0-317) start node error -12: Cannot allocate memory

and I get no sound at all. I get the problem with or without the patched kernel, (so with vendor = 1 or vendor = 0).

Without your module, so using the standard snd_usb-audio, the card works, but I get the infamous MOTU channel hopping problem which I wanted to solve....

Any ideas?

Thank you in advance for your help!

Hi Drumfix,

Thanks for providing this code! I have a MOTU 24Ao in the lab and am trying to control it from a PC running Ubuntu 20.04. I am also experiencing some issues with it suddenly stopping in the middle of playback and channels switching (especially when using an USB extension cable between sound card and PC) and I was hoping this driver would fix that. However, I have some problems compiling and installing the driver and was hoping you could help. I have only a little programming experience, so sorry if this is a trivial question.

So, I installed the kernel source code by downloading it from https://github.com/zen-kernel/zen-kernel/tags and extracting them into/lib/modules/uname -r/source as @ozel suggested. But when I try to run make I get the following: _Copying required header files from kernel sources... '/lib/modules/5.11.0-41-generic/source/sound/usb/usbaudio.h' -> '/home/audiologie/Documents/motu-avb-usb-main/usbaudio.h' '/lib/modules/5.11.0-41-generic/source/sound/usb/midi.h' -> '/home/audiologie/Documents/motu-avb-usb-main/midi.h' make -C ""/lib/modules/5.11.0-41-generic/build"" M="/home/audiologie/Documents/motu-avb-usb-main" modules make[1]: Entering directory '/usr/src/linux-headers-5.11.0-41-generic' CC [M] /home/audiologie/Documents/motu-avb-usb-main/motu.o MODPOST /home/audiologie/Documents/motu-avb-usb-main/Module.symvers LD [M] /home/audiologie/Documents/motu-avb-usb-main/motu.ko BTF [M] /home/audiologie/Documents/motu-avb-usb-main/motu.ko Skipping BTF generation for /home/audiologie/Documents/motu-avb-usb-main/motu.ko due to unavailability of vmlinux make[1]: Leaving directory '/usr/src/linux-headers-5.11.0-41-generic' _

I don't know if this is an error or just a warning that can be ignored, but if I then try to do sudo make install I get the following errors: _make -C ""/lib/modules/5.11.0-41-generic/build"" M="/home/audiologie/Documents/motu-avb-usb-main" modules_install make[1]: Entering directory '/usr/src/linux-headers-5.11.0-41-generic' INSTALL /home/audiologie/Documents/motu-avb-usb-main/motu.ko At main.c:160:

• SSL error:02001002:system library:fopen:No such file or directory: ../crypto/bio/bss_file.c:69
• SSL error:2006D080:BIO routines:BIO_new_file:no such file: ../crypto/bio/bss_file.c:76 sign-file: certs/signing_key.pem: No such file or directory DEPMOD 5.11.0-41-generic Warning: modules_install: missing 'System.map' file. Skipping depmod. make[1]: Leaving directory '/usr/src/linux-headers-5.11.0-41-generic' depmod -A _

I really have no clue how to fix this, could you please help?

Best, Maartje