Archer C7 2.4 GHz wireless dies in 24~48 hours

mk24 · 2020-03-16T15:03:43.059Z

Try completely shutting down 5 GHz and test heavy use on 2.4 only. This could differentiate if there really is a relation to the 5 GHz. It could be that 2.4 itself has a problem.

metric · 2020-03-17T00:15:42.917Z

@Gruntruck My experience has been the same. Two low traffic IoT clients chug along for a long time. Introduce one streaming and/or gaming machine and it goes south fast. BTW This happens only on wireless. Ethernet switch works just fine on any load.

metric · 2020-03-17T00:19:24.611Z

@mk24. I was using in that mode when it failed all the time. 5 Ghz was not configured at all.

Now I am using both 2.4GHz and 5 GHz. It seems to be working for 24 hours and have a cron job that reboot the router every night.

uweklatt · 2020-03-29T13:48:24.950Z

Hello,

I have the same problem with 2.4GHz on Archer C7 v2.
After upgrading my uplink from 100 Mbit/s to 1 GB/s the 2.4 Wifi dies a lot more frequently...
5GHz is still running fine.

When the error occurs, the following message is logged in syslog:

Sun Mar 29 14:13:06 2020 kern.err kernel: [ 4218.030163] ath: phy1: Unable to reset channel, reset status -5
Sun Mar 29 14:17:27 2020 kern.err kernel: [ 4478.945333] ath: phy1: Unable to reset channel, reset status -5

I was able to reactivate 2.4GHz when executing "wifi" command from SSH console.
Another way is to disable and then reenable 2.4GHz wifi with Luci webinterface.

At the moment I use OpenWrt 19.07.2 r10947-65030d81f3 with:

ath10k-firmware-qca988x, 2019-10-03-d622d160-1
kmod-ath, 4.14.171+4.19.98-1-1
kmod-ath10k, 4.14.171+4.19.98-1-1
kmod-ath9k, 4.14.171+4.19.98-1-1
kmod-ath9k-common, 4.14.171+4.19.98-1-1
kmod-phy-ath79-usb, 4.14.171-1

We should use a small script, that reenables 2.4GHz wifi after this error message.
I have used a modified version of: Ath10k_pci 0000:01:00.0: SWBA overrun on vdev 0, skipped old beacon
Let's see if it helps

Uwe

loyukfai · 2020-03-29T17:30:00.810Z

For some reasons my 2.4GHz is still running after 9 days.... The last configuration parameter I remember changing was disabling legacy rate.

Cheers.

uweklatt · 2020-03-30T11:56:50.383Z

Hello,

after another 2.4GHz shutdown today I had no message in syslog or kernellog

Now I use the following cron script to detect loss of all 2.4GHz clients.
If no client is visible (should not happen), the "wifi" command reconfigures 2.4GHz wifi.

#!/bin/sh
sleep 60
grep -q 0 /sys/kernel/debug/ieee80211/phy1/netdev:wlan1/num_mcast_sta
if [ "$?" -eq "0" ]; then
    sleep 10
    /sbin/wifi
fi

Edit:
The script works! I had another fail and it was catched and recovered by the script.

Uwe

trumee · 2020-04-01T03:44:51.935Z

Its a shame we need to rely on scripts on Archer C7. This router was touted as a star for using openwrt. It seems that openwrt release over the years have become worse.

Gruntruck · 2020-04-01T07:35:37.478Z

It is not OpenWRT per se that is failing, it is ath9k 2.4GHz firmware blob that is buggy. I now only use 5GHz on all my C7 dumb-AP's and it is rock solid. It seems that whatever 2.4GHz blob that is "baked" into distro is buggy. Perhaps we should try with some very old one?

2.4GHz usually kinda works, as long as you do not "load" it with many devices and/or high throughput. This was the issue with Archer C2's as well, so I got rid of those.

trumee · 2020-04-01T17:02:50.786Z

If the old firmware worked well, why are we updating to new ones which is giving so many issues? The QA/QC is clearly broken on Openwrt's part.

shaarkys · 2020-04-02T09:31:29.672Z

Old firmware didn't work for me, nor htt version of ath10k-firmware-qca988x-ct-htt, now I'm testing smallbuffers - kmod-ath10k-ct-smallbuffers. Btw I'm on latest trunk. Also turning off "Disassociate On Low Acknowledgement" didn't work for me.

Gruntruck · 2020-04-02T13:30:20.295Z

I was never able to make 2.4G work well on OpenWRT C7 distro regardless of version. On the other hand, 5GHz always worked flawlessly. (Same with Archer C2). As far as I understand, ath9k firmware blob bundled with OpenWRT is somewhat "closed source" so only thing you can do is roll with factory blob and hope for the best. Unfortunately, something is not playing nice with OpenWRT.

Also, this was never actualized enough as 2.4G "mostly" works. Bug is unlikely to be triggered by someone with two devices sitting on ADSL. But if you have >100Mbit WAN and many devices, chances are you will trigger it. I just use C7's as 5GHz AP's/edge switches and that's where they excel.

uweklatt · 2020-04-11T15:04:51.018Z

After switching 2.4 GHz from 40MHz Bandwidth to 20MHz, it looks a lot more stable! - Until now I had no issues after this change.

Uwe

shaarkys · 2020-04-12T08:45:43.872Z

I can confirm as well...since then no issues at all.

Archer C7 V2 - Massive Problems Installing and Using OpenWrt

It seems that using the build I posted config above (developers build), drivers ath10k-firmware-qca988x-ct-htt and kernel optimized driver kmod-ath10k-ct-smallbuffers, in combination with 20 MHz bandwidth, is working solution for me - all 2.4 GHz connections are so far stable.

uweklatt · 2020-04-14T18:01:30.352Z

Hello again,

limiting 2.4GHz to 20MHz bandwidth makes my device rock stable.

I have two 2.4GHz networks with permanent traffic and an additional (not shown) 5GHz network:

Bild4868×439 71.6 KB

Now the developers must find the reason for this

Uwe

Pocket_Sevens · 2020-04-14T20:38:06.849Z

uweklatt:

Hello again,

limiting 2.4GHz to 20MHz bandwidth makes my device rock stable.

Is that with ath10k-firmware-qca988x-ct-htt and kmod-ath10k-ct-smallbuffers? Or is that with just changing the bandwidth to 20MHz?

uweklatt · 2020-04-14T21:07:31.502Z

Hello Pocket_Sevens,

actually I am using ath10k-firmware-qca988x-ct-htt and kmod-ath10k-ct.

Uwe

muchtall · 2020-04-23T22:23:15.731Z

Thanks @uweklatt!

I made some modifications to your script and made it into a function suitable to be placed in System > Startup > Local Startup, ie:

# Put your custom commands here that should be executed once
# the system init finished. By default this file does nothing.

### Keep an eye on the 2.4GHz ath9k interface and restart it if no clients are connected
wifi24watchdog() {
  while true ; do
    sleep 60
    grep -q 0 /sys/kernel/debug/ieee80211/phy1/netdev:wlan1/num_mcast_sta
    if [ "$?" -eq "0" ]; then
      /sbin/wifi
      logger wifi24watchdog restarted the 2.4 GHz radio
    fi
  done
}
wifi24watchdog &

exit 0

This also invokes logger so you can keep track of how often this is firing in the System Log.

uweklatt · 2020-04-24T08:03:34.554Z

Hello,

after limiting 2.4GHz to 20MHz bandwidth my Archer C7 v2 runs continously since April 11. without additional scripts or reboots...

Uwe

SlotTech · 2020-04-24T11:00:55.637Z

While switching to 20MHz prolonged the inevitable it's not a solution for me, the 2.4GHz dropped twice in the past 4 days.

primoz · 2020-04-25T20:10:09.827Z

Switching to 20 MHz doesn't work for me. I also tried all combinations of firmware and kernel modules for 5 GHz. I have latest stable LuCI 19.07.

I'm also posting testing procedure, so anyone can reproduce this problem. You can use iperf on 2,4 GHz SSID and it will fail in hours.

open ssh to router
opkg update
opkg install iperf3
iperf3 -s
download iperf client on PC - https://iperf.fr/iperf-download.php
connect to 2,4 GHz SSID
iperf3.exe -c 192.168.1.1 -t 86400 (change IP to your router IP)
the connection will fail after 1-3 hours