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In the answer by Chili555 for How do I create a system file /etc/modprobe.d/ath9k.conf? it is shown that you can create a config file for a kernel module . Now the question is how do I verify that the options set in that config file have taken effect after sudo modprobe ath9k ?

Specific option that I am trying to check is ps_enable. However, doing the following

$ modinfo ath9k | grep ps_enable

parm:           ps_enable:Enable WLAN PowerSave (int)

only explains what the parameter is and not its current value.

Apparently such information is contained within /sys filesystem. According to Gilles's answer on the relevant post, in order to find the driver in use by interface you would execute

readlink /sys/class/net/wlan0/device/driver

which would provide the relative path as in

../../../../bus/pci/drivers/ath5k

In my case due to systemd and predictive interface naming, the interface is named differently and produces

$  readlink /sys/class/net/wlp2s0/device/driver

../../../../bus/pci/drivers/ath9k

The resulting directory path contains subdirectories module/parameters/ where there will be files for each parameter containing their current value. Thus, if I edit the /etc/modprobe/ath9k.conf file and reinsert the module, the result is as follows:

# After editing the conf file to set parameter to 1

$ sudo sh -c 'modprobe -r ath9k ; sleep 3; modprobe ath9k'

$ sudo cat  /sys/class/net/wlp2s0/device/driver/../../../../bus/pci/drivers/ath9k/module/parameters/ps_enable

1

# after editing the file and setting parameter to 0

$ sudo sh -c 'modprobe -r ath9k ; sleep 3; modprobe ath9k'

$ sudo cat  /sys/class/net/wlp2s0/device/driver/../../../../bus/pci/drivers/ath9k/module/parameters/ps_enable

0

The command can be combined as well.

$ cat  "$(readlink -f /sys/class/net/wlp2s0/device/driver/)"/module/parameters/ps_enable

0

If you do have desktop environment and dbus running, as well as qdbus or dbus-send installed, such information can be queried via Network Manager's dbus interface ( though it requires figuring out the object path of each individual device, and probably would be better written in Python or C )

$ qdbus --system org.freedesktop.NetworkManager /org/freedesktop/NetworkManager/Devices/14 org.freedesktop.NetworkManager.Device.Driver

ath9k