mt7620 - dropping frames (WiFi)

Username: A

Origin: https://bugs.openwrt.org/index.php?do=details&task_id=896

Device: Nexx WT3020 (MT7620)

LEDE release: LEDE Reboot 17.01-SNAPSHOT r3435-65eec8bd

Latest LEDE on Nexx WT3020 with MT7620 is getting syslog spammed with:

ieee80211 phy0: rt2x00queue_write_tx_frame: Error - Dropping frame due to full tx queue 2

It usually occurs with high-bandwidth usage of WiFi client (Android i.e.) and results with need to reboot router (or WiFi won’t even work for devices - it’s seen but unable to connect).

cat /etc/config/wireless

config wifi-device 'radio0' option type 'mac80211' option hwmode '11g' option path 'platform/10180000.wmac' option country 'PL' option disabled '0' option htmode 'HT40' option distance '3' option txpower '20' option channel '6'

config wifi-iface option device 'radio0' option mode 'ap' option ssid 'xxx' option network 'lan' option encryption 'psk2+ccmp' option key 'xxx'

Also it’s connected with the issue of android devices loosing connectivity/dropping wifi even 1 meter next to router:

Fri Jul 7 00:32:11 2017 daemon.info hostapd: wlan0: STA xx:xx:xx:xx:xx:xx IEEE 802.11: authenticated Fri Jul 7 00:32:11 2017 daemon.info hostapd: wlan0: STA xx:xx:xx:xx:xx:xx IEEE 802.11: associated (aid 2) Fri Jul 7 00:32:11 2017 daemon.notice hostapd: wlan0: AP-STA-CONNECTED xx:xx:xx:xx:xx:xx Fri Jul 7 00:32:11 2017 daemon.info hostapd: wlan0: STA xx:xx:xx:xx:xx:xx WPA: pairwise key handshake completed (RSN) Fri Jul 7 00:32:51 2017 daemon.info hostapd: wlan0: STA xx:xx:xx:xx:xx:xx IEEE 802.11: disconnected due to excessive missing ACKs Fri Jul 7 00:32:51 2017 daemon.notice hostapd: wlan0: AP-STA-DISCONNECTED xx:xx:xx:xx:xx:xx Fri Jul 7 00:32:55 2017 daemon.info hostapd: wlan0: STA xx:xx:xx:xx:xx:xx IEEE 802.11: authenticated Fri Jul 7 00:32:55 2017 daemon.info hostapd: wlan0: STA xx:xx:xx:xx:xx:xx IEEE 802.11: associated (aid 2) Fri Jul 7 00:32:55 2017 daemon.notice hostapd: wlan0: AP-STA-CONNECTED xx:xx:xx:xx:xx:xx Fri Jul 7 00:32:55 2017 daemon.info hostapd: wlan0: STA xx:xx:xx:xx:xx:xx WPA: pairwise key handshake completed (RSN)