This is not an Ardour problem, but maybe someone here can help.
I have an Mbox 2 USB audio interface and after I wake my computer from sleep, the input of the USB interface is not responding and appears as it has 100% signal.
As Robin says this is likely a problem with the driver (kernel module), or possibly even related to the hardware/firmware of the sound card. Restarting higher level services is unlikely to help.
You should contact the driver developer to try to get the problem fixed (if it’s fixable on that side).
Meanwhile, as tentative workarounds, you may try to use “usbreset” as suggested by groundsquirrel. If that does not work you may try to unload and then reload the related kernel modules (e.g., snd-usb-audio, etc), or a combination of both things.
Even that is not guaranteed to work, though: the sound card hardware/firmware may be in a state which requires an actual power-cycle to get back to work properly. If that’s the case, your only option is to avoid your system to go into sleep mode. The fact that the card is not completely unresponding and it’s partly working is a good sign, though.
P.S.: in Debian and Ubuntu (and likely other distro as well), the “usbreset” command is included in the “usbutils” package (thus no need to build it yourself from sources). If it’s not already done, just install that package (e.g., apt install usbutils).
Great responses, usbreset works!
The input is now working normally (not at 100%).
However, now I would have to turn off my speakers before running the command.
If I don’t, I get a loud noise, just like what happens when I plug/unplug the devise.
I don’t know what this sound is called or if it has a particular name.
This is a step in the right direction, I contacted the developer of the Mbox drivers, but no response yet.
I wanted to pay him (or someone else) to fix the issue of the drivers, if possible.