I have upgraded from 18.06.4 to 19.07, same issue.
Then I upgraded from 19.07 to 19.07.01, same thing.
Then I replaced ath10k-firmware-qca988x-ct with ath10k-firmware-qca988x and kmod-ath10k-ct with kmod-ath10k, same thing.
Is there any way of using 2.4GHz on Archer C7 v2 while retaining 5GHz?
One question: according to info in another thread, 2.4GHz radio is using ath9k drivers and 5GHz radio is using ath10k drivers. In that case, changing ath10k should have zero effect on 2.4GHz radio stability?
no i don't. i don't have firmware sources to see what has been changed in between the two versions and even if i had it would still need some debugging...
wrong bits coming from PCI device's driver or firmware to the main SOC (WMAC integrated-2.4GHz) can cause entire system instability or crash (that's why 2.4wifi is not an exception here) and i've seen this personally while working with QCA9880 v1 (don't think QCA9880 v2 is much different)
OK. Yes, it is plausible that buggy 5GHz firmware might affect 2.4GHz radio...
I have found evidence in some other threads that ath10k indeed affects 2.4 even if it should not to:
I am now testing "backdated" ath10k driver so we will see how it goes. If nothing happens within 2 days then it works! And if it is stupid but works then it is not stupid!
It has been 3 days and 2.4GHz is still working without issues.
This C7 is run as dumb AP and has 2.4GHz segregated as "guest" WiFi and 5GHz as LAN WiFi with fairly high load.
Conclusion: for some odd reason, using backdated ath10k firmware (for 5GHz radio!) fixes issues with 2.4GHz radio. With other words, it seems that "stock" 19.07.1 firmware on Archer C7 v2 has buggy 2.4GHz and you must reshuffle ath10k drivers to make it work
Hmm. I also feel like 2.4 ghz Problems even if 5ghz runs fine with 19.7.1. switched to ath10k non ct drivers and despite some sudden reboots dont experience the range and stability Problems anymore
It has now been online for 4 days and subjected to load that usually brings it down within 24 hours. It definitely works, despite it should not. Both 5GHz and 2.4GHz rock solid. Perhaps someone can do some more intricate debbuging on why 5G firmware bugs 2.4G radio?
This is my "magic mix" for fully functioning Archer C7 v2 with 19.071 image:
2.4GHz stopped responding today. Failure mode was slightly different: some of associated stations were still associated but could not send anything. I tried connecting a phone to 2.4GHz, it would associate but not surf. Two hours later it could connect and surf.
Anyway, 2.4GHz is still dodgy on Archer C7 v2 and replacing ath10k stuff seems not to fix the issue!
The issues manifest themselves when you have multiple connections. I have 6 clients, 1Gb fiber connection and after few days, it will bring 2.4GHz down. If you use low bandwidth single client and have ADSL you will unlikely experience same kind of issues.
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.
@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.
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:
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.
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.
