Comment 0 for bug 1672740

We hit the following problem about the interaction between netplan and the ath9k_htc module, controlling the chip Atheros AR9271.

If you run the following command

    netplan --debug apply

or you use console-conf for setting the network interfaces we get the following messages :

** (generate:2261): DEBUG: Processing input file //etc/netplan/00-snapd-config.yaml..
** (generate:2261): DEBUG: eth0: setting default backend to 1
** (generate:2261): DEBUG: Generating output files..
** (generate:2261): DEBUG: NetworkManager: definition eth0 is not for us (backend 1)
DEBUG:netplan generated networkd configuration exists, restarting networkd
DEBUG:no netplan generated NM configuration exists
DEBUG:device lo operstate is unknown, not replugging
DEBUG:device eth0 operstate is up, not replugging
DEBUG:replug wlan0: unbinding 4-1:1.0 from /sys/bus/usb/drivers/ath9k_htc
DEBUG:replug wlan0: rebinding 4-1:1.0 to /sys/bus/usb/drivers/ath9k_htc

The last two row show two consecutive actions, one soon after the other: unbind and bind the usb device on usb hub.

The module ath9k_htc doesn't work fine in this situation: the wireless interface disappears.

Our problem can be fixed by using the same approach used for mac80211_hwsim e mwifiex_pcie modules.
The attached patch file fix the issue following the same pattern adopted for the following modules:
mwifiex_pcie,mac80211_hwsim.