[FS#849] LEDE commit 61cfc8075b615c231cf6349b3708d0a7e073613e broke adhoc connectivity on TP-LINK DIR-810L-A1

[LEDE Bugs]

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

User who did this - Alvaro Lopez Antelo (AlverGant) 

Attached to Project - LEDE Project
Summary - LEDE commit 61cfc8075b615c231cf6349b3708d0a7e073613e broke adhoc connectivity on TP-LINK DIR-810L-A1
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Low
Priority - Very Low
Reported Version - Trunk
Due in Version - Undecided
Due Date - Undecided
Details - I have been experimenting with mesh networking using batman-adv V on a number of devices (WDR-3600, WR-740, DIR-505 and DIR-810l) on LEDE 17.01.1 with great success but recently did an upgrade compiling to the master branch of LEDE (r4018-4b195a6) with batman-adv 2017.0 and D-Link DIR-810l loosed all connectivity, although other Atheros platforms had no problems whatsoever.

I have traced the problem to commit id 61cfc80, reverting to the previous commit (3d71d1d) resolved the issues.

The problem is not batman-adv related, what happens is that although adhoc interfaces apparently connect normally on the affected device, they are only able to hear other nodes but not to transmit, none of the other devices receive any packets from DIR-810L. I have not tested using "normal" interfaces like access point or station, only adhoc, but I can confirm that reverting the commit to the previous one with the same configuration resolved the issue of no wireless adhoc connectivity.

Other symptoms are:

Warnings on log messages regarding the driver support for the power amplifier (they don't show up on the previous commit)
Mon Jun 12 16:09:10 2017 kern.warn kernel: [ 25.122709] ieee80211 phy0: rt2800_config_channel: Warning - Using incomplete support for external PA
Mon Jun 12 16:09:10 2017 kern.info kernel: [ 25.203270] IPv6: ADDRCONF: adhoc0: link is not ready
Mon Jun 12 16:09:10 2017 kern.info kernel: [ 25.316852] adhoc0: Created IBSS using preconfigured BSSID 02:ca:fe:ca:00:12
Mon Jun 12 16:09:10 2017 kern.info kernel: [ 25.330980] adhoc0: Creating new IBSS network, BSSID 02:ca:fe:ca:00:12
Mon Jun 12 16:09:10 2017 kern.warn kernel: [ 25.346636] ieee80211 phy0: rt2800_config_channel: Warning - Using incomplete support for external PA

Incomplete station info (lack of RX expected throughput and low TX throughput for the high signal level)
root at node-1:~# iwinfo adhoc0 assoclist
EC:08:6B:EC:3F:A4 -20 dBm / unknown (SNR -20) 170 ms ago
RX: unknown 8830 Pkts.
TX: 6.5 MBit/s, MCS 0, 20MHz 601 Pkts.

And chipset detection apparently wrong (bellow a comparison log taken from trunk and 17.01.1
On master branch: ieee80211 phy0: rt2x00_set_rt: Info - RT chipset 6352, rev 0500 detected
On 17.01.1: ieee80211 phy0: rt2x00_set_rt: Info - RT chipset 5390, rev 0500 detected

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=849