8852ce: No packets from 5GHz in Monitor mode

[grutz]

Using a 8852ce module on Ubuntu 22.04 LTS I am able to capture frames on most 2.4 GHz channels when in monitor mode. Low power mode is disabled.

...
[98869.471001] rtw89_8852ce 0000:02:00.0: loaded firmware rtw89/rtw8852c_fw.bin
[98869.480121] rtw89_8852ce 0000:02:00.0: Firmware version 0.27.56.14, cmd version 0, type 1
[98869.480142] rtw89_8852ce 0000:02:00.0: Firmware version 0.27.56.14, cmd version 0, type 3
[98869.757041] rtw89_8852ce 0000:02:00.0: chip rfe_type is 1
...
ubuntu@ubuntu:~$ sudo iw realtekwifi0 set freq 2412
ubuntu@ubuntu:~$ sudo tcpdump -i realtekwifi0
tcpdump: verbose output suppressed, use -v[v]... for full protocol decode
listening on realtekwifi0, link-type IEEE802_11_RADIO (802.11 plus radiotap header), snapshot length 262144 bytes
00:26:02.650167 363978528us tsft 11.0 Mb/s 2412 MHz 11b 0dBm signal antenna 0 Request-To-Send TA:98:18:88:be:f0:04 (oui Unknown)
00:26:02.650362 363978752us tsft 11.0 Mb/s 2412 MHz 11b 0dBm signal antenna 0 Clear-To-Send RA:98:18:88:be:f0:04 (oui Unknown)

As soon as the frequency is moved to a 5 GHz or 6E-enabled channel, no packets:

ubuntu@ubuntu:~$ sudo iw realtekwifi0 set freq 5220
ubuntu@ubuntu:~$ iw dev realtekwifi0 info
Interface realtekwifi0
	ifindex 4
	wdev 0x100000001
	addr 1c:ce:51:91:5b:50
	type monitor
	wiphy 1
	channel 44 (5220 MHz), width: 20 MHz (no HT), center1: 5220 MHz
	multicast TXQ:
		qsz-byt	qsz-pkt	flows	drops	marks	overlmt	hashcol	tx-bytes	tx-packets
		0	0	0	0	0	0	0	0		0
ubuntu@ubuntu:~$ sudo time tcpdump -i realtekwifi0
tcpdump: verbose output suppressed, use -v[v]... for full protocol decode
listening on realtekwifi0, link-type IEEE802_11_RADIO (802.11 plus radiotap header), snapshot length 262144 bytes
^C
0 packets captured
0 packets received by filter
0 packets dropped by kernel
0.01user 0.00system 1:02.67elapsed 0%CPU (0avgtext+0avgdata 7936maxresident)k
0inputs+0outputs (0major+515minor)pagefaults 0swaps

However APs are seen on freq 5220 when doing an iw realtekwifi0 scan process:

...
BSS 8e:18:98:be:f0:04(on realtekwifi0)
	TSF: 715485204454 usec (8d, 06:44:45)
	freq: 5220
	beacon interval: 100 TUs
	capability: ESS Privacy SpectrumMgmt ShortSlotTime RadioMeasure (0x1511)
	signal: -61.00 dBm
	last seen: 2852 ms ago
	Information elements from Probe Response frame:
	SSID: Free-WiFi
	Supported rates: 12.0* 18.0 24.0* 36.0 48.0 54.0
	Country: US	Environment: bogus
...