[FS#643] iwinfo scan reports "Scanning not possible" using mt76 mac80211 driver

[LEDE Bugs]

A new Flyspray task has been opened.  Details are below. 

User who did this - fherbert (fherbert) 

Attached to Project - LEDE Project
Summary - iwinfo scan reports "Scanning not possible" using mt76 mac80211 driver
Task Type - Bug Report
Category - Packages
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Low
Priority - Very Low
Reported Version - lede-17.01
Due in Version - Undecided
Due Date - Undecided
Details - I'm unable to consistently scan for access points using iwinfo.
I'm running a MT7688 chip with the mt76 mac80211 driver on LED 17.01

The scan works very intermittently, but mostly returns "Scanning not possible".

My wireless config looks like:
config wifi-device 'radio0'
	option type 'mac80211'
	option channel '11'
	option hwmode '11g'
	option path 'platform/10300000.wmac'
	option htmode 'HT20'
	option disabled '0'

I've added some debugging code to iwinfo_nl80211.c to try and see where it's failing. To run a scan I use the command: iwinfo radio0 scan
iwinfo creates a temporary interface (tmp.radio0) and then calls nl80211_get_scanlist_nl, this returns a zero length iwinfo_scanlist_entry which causes "Scanning not possible" to be returned.
I'm happy to do some more debugging if I can be pointed in the right direction.

   

 

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=643