WRT1900ACS on 21.02: Apple devices lose connection

Shortly after upgrading from 19.07 to 21.02.0, I've found that my Apple devices lose wireless connectivity.

I've observed this on a MacBook Pro, an iPhone, and an iPad, on both the AC 5GHz and the N 2.4 GHz networks. Windows and Linux (incl. Android) devices are unaffected.

I've tried disabling disassoc_low_ack, but that resulted in the Apple devices staying connected to the network but unable to reach anything (e.g., pings to 192.168.1.1 would go unanswered).

I've not tried disabling WMM yet, because I need it for the videoconferencing my job entails.

# opkg list-installed | grep mwlwifi
kmod-mwlwifi - 5.4.143+2020-02-06-a2fd00bb-2
mwlwifi-firmware-88w8864 - 2020-02-06-a2fd00bb-2
# uci show | grep radio | grep -Ev 'key|ssid|macaddr'
wireless.radio0=wifi-device
wireless.radio0.type='mac80211'
wireless.radio0.channel='36'
wireless.radio0.hwmode='11a'
wireless.radio0.path='soc/soc:pcie/pci0000:00/0000:00:01.0/0000:01:00.0'
wireless.radio0.htmode='VHT80'
wireless.radio0.country='US'
wireless.radio0.cell_density='0'
wireless.default_radio0=wifi-iface
wireless.default_radio0.device='radio0'
wireless.default_radio0.network='lan'
wireless.default_radio0.mode='ap'
wireless.default_radio0.encryption='sae'
wireless.default_radio0.ieee80211w='2'
wireless.radio1=wifi-device
wireless.radio1.type='mac80211'
wireless.radio1.channel='11'
wireless.radio1.hwmode='11g'
wireless.radio1.path='soc/soc:pcie/pci0000:00/0000:00:02.0/0000:02:00.0'
wireless.radio1.htmode='HT20'
wireless.radio1.country='US'
wireless.radio1.cell_density='0'
wireless.default_radio1=wifi-iface
wireless.default_radio1.device='radio1'
wireless.default_radio1.network='lan'
wireless.default_radio1.mode='ap'
wireless.default_radio1.encryption='psk2'
wireless.wifinet2.device='radio1'

Let me know if there's any more info I should provide.

Hi,

I confirm the same here with Iphones 7, 8 and 12.
Only option is to put the apple device on plane mode and reconnect.

Also interested on a solution

I've read that setting DTIM Interval to 3 (Advanced settings) helps apples

I've not found this necessary — cycling Wi-Fi on and off, or switching networks, is sufficient for me.

But that only staves off the problem for an hour or so. I'm not positive about that figure, so I've started a ping from my iPhone to 192.168.1.1 to see exactly how long it can hold a connection.

Let's try this. I will let you know if it's improving the situation.

Check this

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Thanks. Implemented. I'll see in the next days if it's getting better.

I got up to 20476 pings without a single one unanswered. The app I was using kept the screen on the whole time, and I've always noticed a dropped connection immediately after unlocking the phone, so there's another data point to consider. However, the MacBook drops connections even under heavy use.

I'll try shortening the DTIM interval and/or disabling AMSDU tonight.

Seems good until now, running well for the last days.

None of my Apple devices have dropped connections since I disabled AMSDU. Good show. I'll have to look into why Apple devices play ill with that technology.

Meanwhile, here's the specific way I did it:

root@router:~# cat /etc/rc.local
for phy in /sys/kernel/debug/ieee80211/*; do
        echo "0" >> $phy/mwlwifi/tx_amsdu
        logger "AMSDU disabled on $phy."
done
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