Device remains in use after manager is stopped

[jonnylamb]

I get usb.core.USBError: [Errno 16] Resource busy when creating another ant.fs.manager.Application instance using the same device:

With this test script I get the following traceback. https://gist.github.com/jonnylamb/a794c732bff1e1883d1a

Traceback (most recent call last):
  File "/tmp/garmin.py", line 34, in <module>
    b = GarminTest()
  File "/home/jonny/src/openant/ant/fs/manager.py", line 104, in __init__
    self._node = Node()
  File "/home/jonny/src/openant/ant/easy/node.py", line 56, in __init__
    self.ant = Ant()
  File "/home/jonny/src/openant/ant/base/ant.py", line 68, in __init__
    self._driver.open()
  File "/home/jonny/src/openant/ant/base/driver.py", line 185, in open
    dev.set_configuration()
  File "/home/jonny/src/pyusb/usb/core.py", line 559, in set_configuration
    self._ctx.managed_set_configuration(self, configuration)
  File "/home/jonny/src/pyusb/usb/core.py", line 92, in managed_set_configuration
    self.backend.set_configuration(self.handle, cfg.bConfigurationValue)
  File "/home/jonny/src/pyusb/usb/backend/libusb1.py", line 724, in set_configuration
    _check(self.lib.libusb_set_configuration(dev_handle.handle, config_value))
  File "/home/jonny/src/pyusb/usb/backend/libusb1.py", line 554, in _check
    raise USBError(_str_error[ret], ret, _libusb_errno[ret])
usb.core.USBError: [Errno 16] Resource busy

[Tigge]

Yes, this is intended. The Application class takes hold of this in the init function. Might be able to work around this by using del on the first object before creating a new one. But only one Application object is intended to be used during the liftetime of the program. That doesn't stop one from using multiple channels and similar of course.

[jonnylamb]

del a before creating b does not work.

How do you suggest I create another connection in the same process after the first one has disconnected then?

[Tigge]

Yeah, that is a good question - and something I haven't tried yet. I'll experiment a bit with this and see if I can find a good solution for this.

[jonnylamb]

Thanks, would be incredible to get a good solution to this.

Relatedly, after swapping the dev.set_configuration() and dev.reset() calls in ant/base/driver.py I found I could make multiple Application instances (to the same device) but only after receiving a Resource busy exception first, as quoted above.

[drkingpo]

I expect the main solution here will be gracely close the channel.

Will be possible with Pull #54.

Also see examples for this.