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From: Kurt Grutzmacher <grutz@jingojango.net>
Date: Thu, 16 May 2024 09:17:57 -0700
Message-ID: <CAMDnkSkWQqQN-cimuJ--XFEJbdNPJK_z7hocskSaBQbnH+tW=g@mail.gmail.com>
Subject: No packets in monitor mode with rtw89_8852ce
To: linux-wireless@vger.kernel.org
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Using a Realtek 8852ce module in monitor mode on Ubuntu 22.04 LTS I am
able to capture frames on 2.4 GHz channels but not any other
frequencies. 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)

Moving to a 5 GHz or 6E-enabled channel returns no captured packets.
I've tried multiple channels.

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

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

APs are visible on freq 5220 when doing iw realtekwifi0 scan:

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

--
 Kurt Grutzmacher -=- grutz@jingojango.net