Does WIFI 5 GHz work on TP-Link Archer C7 AC1750 with the latest OpenWrt build?

I can confirm the situation described by OP. My router is an Archer C7 V5 running 19.07.1. No problems with the 2.4GHz radio, but 5GHz is not working. There are no error messages in Luci, but the SSID never shows up and clients cannot connect. I replaced kmod-ath10k-ct and ath10k-firmware-qca988x-ct with kmod-ath10k and ath10k-firmware-qca988x. Didn't help.

Did you try to set the country to default and the channel to auto? If not, can you please try that and let me know whether it works or not?
Also by replacing the drivers I assume you mean deleting the current drivers, installing the non-ct version, and rebooting the router, correct?

Yes, I had set the country to default, the channel to auto, replaced the drivers and rebooted.

In Luci, radio0 "Qualcomm Atheros QCA9880 802.11nac" shows the message "Device is not active".

I've done some testing on a V4. The default install of firmware-ct and ath10k-ct does not work. Replacing with ath10k-ct-smallbuffers will work, as does replacing both the firmware and kmod with non-ct. This is with country set to US and a single AP operating on channel 124 with 20 MHz bandwidth (VHT20). 124 is a DFS channel in the US.

@whyfi could you post the parts of the system log related to wifi failing? Attempt to re-start wifi this should cause the errors to be logged at the end.

This is the error message related to radio0: HOSTAPD_START_FAILED

Sat Feb 15 12:40:19 2020 daemon.notice netifd: radio0 (2298): WARNING (wireless_add_process): executable path /usr/sbin/wpad does not match process 2242 path ()
Sat Feb 15 12:40:19 2020 daemon.notice netifd: radio0 (2298): Device setup failed: HOSTAPD_START_FAILED

19.07.1 doesn't seem very stable based on the above. :frowning:

How about 18.06.7 ar71xx? Did anyone use that? What are the major differences between 18.06.7 and 19.07.1?

Also, does anyone know about a safe way to return to the stock TP-Link firmware from OpenWRT?

Please use the forum search or open a new topic for this question.

I tried with both 19.07.0 and 19.07.1, neither works.

Here is the full syslog extract showing the errors:

Sun Feb 16 19:44:31 2020 daemon.err hostapd: Configuration file: /var/run/hostapd-phy0.conf
Sun Feb 16 19:44:32 2020 kern.warn kernel: [93452.335325] ath10k_pci 0000:00:00.0: pdev param 0 not supported by firmware
Sun Feb 16 19:44:32 2020 daemon.notice hostapd: wlan0: INTERFACE-ENABLED
Sun Feb 16 19:44:32 2020 kern.info kernel: [93452.355599] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
Sun Feb 16 19:44:32 2020 daemon.notice hostapd: wlan0: INTERFACE-DISABLED
Sun Feb 16 19:44:32 2020 daemon.err hostapd: nl80211: Could not configure driver mode
Sun Feb 16 19:44:32 2020 daemon.notice hostapd: nl80211: deinit ifname=wlan0 disabled_11b_rates=0
Sun Feb 16 19:44:32 2020 daemon.err hostapd: nl80211 driver initialization failed.
Sun Feb 16 19:44:32 2020 daemon.notice hostapd: wlan0: interface state UNINITIALIZED->DISABLED
Sun Feb 16 19:44:32 2020 daemon.notice hostapd: wlan0: AP-DISABLED
Sun Feb 16 19:44:32 2020 daemon.notice hostapd: wlan0: CTRL-EVENT-TERMINATING
Sun Feb 16 19:44:32 2020 daemon.err hostapd: hostapd_free_hapd_data: Interface wlan0 wasn't started
Sun Feb 16 19:44:32 2020 daemon.notice netifd: radio0 (10812): WARNING (wireless_add_process): executable path /usr/sbin/wpad does not match process 2790 path ()
Sun Feb 16 19:44:32 2020 daemon.notice netifd: radio0 (10812): Device setup failed: HOSTAPD_START_FAILED

My router is TP-Link Archer C7 v4. I tried the 3 ath10k firmwares and modules. I confirm the 5Ghz is not usable despite many attempts. OpenWrt 19.07.1.
I am ready to run some experiments if it may help.
Thank you - Regards

On Archer A7 v5 (should be same as C7 v5) 5GHz works for me after:

opkg update && \
  opkg remove wpad-basic ath10k-firmware-qca988x-ct && \
  opkg install wpad-openssl ath10k-firmware-qca988x-ct-htt

wpad-openssl is to enable fast roaming, 5Ghz works with wpad-basic, see OpenWrt 19.07.0 first stable release

Which version of Archer C7? There are 4 different versions I know of. I runt Archer C7 v2 and 5GHz works fine with 19.07.1.

Hi,

According to this info https://openwrt.org/packages/pkgdata/wpad-basic wpad-basic contains 802.11r support already? is wpad-openssl really needed for roaming? (802.11r is fast roaming)

It works OK on my C7V4, after swapping kmod-ath10k-ct to kmod-ath10k-ct-smallbuffers. Still running the ath10k-firmware-qca988x-ct.

Mine is a very basic wireless config running a single AP (non-WDS), psk2 encryption, country US and channel 124. If you're having trouble start by cutting the config down to a simple single AP.

I don't know for sure if wpad-basic supports fast roaming.
wpad-openssl comes from 802.11r (Fast-Roaming) in LUCI, but it's for older openwrt and talks about replacing wpad-mini with wpad

There is no wpad-mini in 19-07. It comes with wpad-basic by default and it has 802.11r option visible in UI. So I believe you do not need to replace it with full wpad just to enable fast roaming.

Hi everyone,

For those of you who had trouble with 19.07.1, is it still a problem with 19.07.2?

Thanks!

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I have both Archer A7 and C7 v5. I never ran 19.07.1 on them but on 19.07 or some pre-release the 5 GHz was unusable. However, now with 19.07.2 the speed seems to be fine with default drivers.

Even then, for some reason choosing TKIP for WPA2 limits the bandwidth to 20 MHz and the speed to some 20 Mbit/s. I really didn't knew that it could have such effect. Is it a feature or bug? Choosing AES solved that. Apparently, you shouldn't be using TKIP also due to its security weaknesses.

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Hi all, I just installed 19.07.3 r11063-85e04e9f46 earlier today on a TP-Link Archer C7 v1.1, and ran into this same problem. The 2.4 Ghz band is working well as radio0, but no radio device is presented to configure a 5 Ghz wireless.

I could not find any kernel modules corresponding to any of the ones mentioned by various users in the thread. I searched using lsmod and also manually looked inside /lib/modules/4.14.180/. The only modules remotely similar to the ones mentioned on my box are ath.ko, ath9k.ko, ath9k_common.ko & ath9k_hw.ko.

Also the hostapd -v shows v2.9 btw.

Does anyone know if a reliable solution exists yet for this problem, which various users seem to be running into, despite continued updates.

5 Ghz was never supported on the v1.1. This topic is about a v5 which is supported.

See https://openwrt.org/toh/tp-link/archer-c7-1750

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somehow I missed that, thanks for clarifying