Wireless 802.11ac test case has been skipped

[Danny Hsu]

[Steps to reproduce]
The Realtek RTL8821CE 802.11ac PCIe Wireless Network Adapte can support 802.11 ac/b/g/n
https://www.realtek.com/en/products/communications-network-ics/item/rtl8821ce
But when running Checkbox Wireless test, the AC test case are skipped, it will shows "job cannot be started: resource expression "wireless_sta_protocol.wlp2s0_ac == 'supported'" evaluates to false"

Can connect to AC AP by manual:
u@u:~$ iwconfig
wlp2s0 IEEE 802.11AC ESSID:"ubuntu-cert-ac-open-tpelab" Nickname:"<WIFI@REALTEK>"
          Mode:Managed Frequency:5.745 GHz Access Point: C8:D3:A3:68:99:45
          Bit Rate:434 Mb/s Sensitivity:0/0
          Retry:off RTS thr:off Fragment thr:off
          Power Management:off
          Link Quality=73/100 Signal level=53/100 Noise level=0/100
          Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
          Tx excessive retries:0 Invalid misc:0 Missed beacon:0

[Additional information]
Image: pc-stella-cmit-bionic-amd64-X00-20191205-806
Manifest: canonical-oem-stella-bionic-amd64-806
system-manufacturer: HP
system-product-name: HP ProOne 400 G5 23.8-in All-in-One
bios-version: R12 Ver. 02.03.01
CPU: Intel(R) Core(TM) i7-9700 CPU @ 3.00GHz (8x)
GPU: 00:02.0 VGA compatible controller [0300]: Intel Corporation Device [8086:3e98] (rev 02)
kernel-version: 4.15.0-1065-oem

[Danny Hsu (dannyhsu)]

Automatically attached

[Danny Hsu (dannyhsu)]

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[Danny Hsu (dannyhsu)]

Automatically attached

[Danny Hsu (dannyhsu)]

Automatically attached

[Sylvain Pineau (sylvain-pineau)]

@Danny do this simple test:

$ iw list | grep VHT

VHT means very high throughput (VHT) as opposed to 802.11n's high throughput (HT) or earlier.

if checkbox reports that ac is not in the iw capabilities it could mean that the SUT connects to the AP at lower rates (80211n only). I all depends on the ap, some are configured to accept a/b/g/n/ac and others just ac.

For reference, https://www.intel.com/content/www/us/en/support/articles/000024678/network-and-io/wireless-networking.html :

(Wireless) Mode

This setting controls the type of Wi-Fi devices (802.11a/b/g/n/ac) that can connect to the AP.
For optimal performance and compatibility, enable support for all wireless modes.
If configured for 11ac mode only, legacy devices that support only 11n or 11a/g aren't able to connect to the AP.

[Danny Hsu (dannyhsu)]

Hi Sylvain,

There is no result after input $ iw list | grep VHT, but it can connected to 11ac mode only, please see the attached.

[Sylvain Pineau (sylvain-pineau)]

Danny, please attach the output of iw list. I'll check if we can find some additional info to state that ac is indeed supported. Must be a driver problem. It's a pity that VHT capabilities are not recorded by iw. it was reliable until then.