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[Fixed] Linux: USB Overflows

Bzerk

New Member
Hi AlbertA, yesterday evening, I tried to record something with bitwig and it froze completely the system. Once bitwig was started and the sound engine initialized -> freeze and only the keyboard leds where blinking. I rebooted and tried again, but same result. It was the only software running and I selected alsa driver for output (on the AXE FX2).
I have a 16.04 and updated (I did not do that for a long time) but still on a 16.04. I re-installed you snd-usb driver from launchpad but I had the same result. Would you have an idea about this? Is there something I can do to make it work?

Bzerk
 

AlbertA

Power User
Hi AlbertA, yesterday evening, I tried to record something with bitwig and it froze completely the system. Once bitwig was started and the sound engine initialized -> freeze and only the keyboard leds where blinking. I rebooted and tried again, but same result. It was the only software running and I selected alsa driver for output (on the AXE FX2).
I have a 16.04 and updated (I did not do that for a long time) but still on a 16.04. I re-installed you snd-usb driver from launchpad but I had the same result. Would you have an idea about this? Is there something I can do to make it work?

Bzerk
It's probably the annoying dkms bug where they use the module version info (which can be just a hash of the files) as comparison and won't install unless the new version number is strictly higher.

Do modinfo snd-usb-audio, the first line should tell you where the module is being picked up. It should be picked up from /lib/modules/<your kernel version>/updates/dkms/ . If it's not then you'll have to manually invoke dkms to force the install like:

sudo dkms uninstall -m snd-usb-audio -v 4.10
sudo dkms install --force -m snd-usb-audio -v 4.10
 

Bzerk

New Member
I will try that, but the latest provided on lauchpad for xenial is 4.9.
My installed kernel is 4.4.0.

I saw that 4.10 is for the next version, can we force install without breaking stuff?
 

AlbertA

Power User
I will try that, but the latest provided on lauchpad for xenial is 4.9.
My installed kernel is 4.4.0.

I saw that 4.10 is for the next version, can we force install without breaking stuff?
If you get broken sound you can always uninstall it and go back to the distro version.
 

AlbertA

Power User
I will try that, but the latest provided on lauchpad for xenial is 4.9.
My installed kernel is 4.4.0.

I saw that 4.10 is for the next version, can we force install without breaking stuff?
I just updated the package for xenial as well. I briefly tested the install on a xenial virtual machine and seems to work fine.
 

Geoff

Member
This is great. I've used linux on and off for years, and was thinking that when my current mac died i would try a linux desktop again.
 

volt

Inspired
Updated openSUSE Tumbleweed to kernel 4.10 last night and right now playing music over the Axe-Fx II since more than two hours. No buffer overflows with USB buffer size set to 64. :)

Thanks again and congrats @AlbertA!
 

AlbertA

Power User
So the Axe-Fx 3 uses a similar configuration as the Axe-Fx 2, asynchronous output with implicit feedback endpoints.

The good news is that it now seems to follow the USB 2 spec more closely, i.e. the output endpoint number is 1, and the implicit feedback endpoint is also #1 as the spec requires. In the Axe-Fx 2, these numbers didn't match (2 and 6 respectively).

However, given the vague wording on the spec about associating these endpoints (they say nothing about not being in the same interface descriptor or in separate ones) the current snd-usb-audio driver just assumes both endpoints should belong to the same interface descriptor. Which means a similar quirk for the Axe-Fx 3 has to be added to the snd-usb-audio module to properly configure the sync endpoint and avoid overflows at the Axe-Fx 3.

Interestingly, there's another product that uses a similar configuration, the Behringer UFX1204, in addition to the M-Audio Fast Track cards.

I was hoping someone would have added support by now, for looking for implicit feedback endpoints in other interface descriptors. Maybe someday when I have more time.
 
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