'active' monitor mode flag can't be set on Raspberry Pi OS Lite

[xdavidhu]

Hi,

My setup looks like this:

• Raspberry Pi 3 Model B v1.2 (Raspberry Pi OS Lite 2020-08-20)
• ALFA AWUS036AC (RTL8812AU) card

I am able to put the device in monitor mode, but setting the active (ACK incoming unicast packets) monitor mode flag fails with Operation not supported (-95):

pi@raspberrypi:~$ sudo iw dev wlan1 set type monitor
pi@raspberrypi:~$ sudo iw dev wlan1 set monitor active
command failed: Operation not supported (-95)

I have tried both v5.6.4.2 and v5.8.5 branches without success.
Should this driver support this flag? Is it maybe something I can just toggle in the Makefile?

Thank you for your help!

[M0tix]

Not sure if you still care, but I'm currently looking at active monitor mode and "enabling" it in the drivers, and you might be interested in this: morrownr/USB-WiFi#73
As for the device, maybe it just doesn't support active monitoring mode.