ftdi_error_return(-4, "usb_open() failed");
#ifdef LIBUSB_HAS_GET_DRIVER_NP
- // Try to detach ftdi_sio kernel module
- // Returns ENODATA if driver is not loaded
+ // Try to detach ftdi_sio kernel module.
+ // Returns ENODATA if driver is not loaded.
+ //
+ // The return code is kept in a separate variable and only parsed
+ // if usb_set_configuration() or usb_claim_interface() fails as the
+ // detach operation might be denied and everything still works fine.
+ // Likely scenario is a static ftdi_sio kernel module.
if (usb_detach_kernel_driver_np(ftdi->usb_dev, ftdi->interface) != 0 && errno != ENODATA)
detach_errno = errno;
#endif