Error in pcap_activate: That device doesn't support monitor mode

[krzysztofkuczek]

Hi, I trying to make gs works on RPI4 running openhd kernel 6.1.29-v8+ and openhd rtl drivers for my TP-Link RTL8812AU Archer T4U 802.11ac wifi adapter. Unfortunelty it does not work even when the wifi seems to be in monitor mode

iw wlan1 info
Interface wlan1
        ifindex 6
        wdev 0x300000001
        addr c4:e9:84:09:07:35
        type monitor
        wiphy 3
        channel 1 (2412 MHz), width: 20 MHz, center1: 2412 MHz
        txpower 18.00 dBm

The error is " Error in pcap_activate: That device doesn't support monitor mode" and tcpdump also claims the same

 sudo tcpdump --monitor-mode -i wlan1
tcpdump: wlan1: That device doesn't support monitor mode

Any idea what i do wrong, thank you in advance Kris

[RomanLut]

sudo apt-get install aircrack-ng sudo airmon-ng start wlan1

Then use wlan1mon.

[krzysztofkuczek]

Hi, DO you mean that another wlan1mon adapter should be available? It's not, and wlan1 still does not work :(

sudo airmon-ng start wlan1

PHY Interface Driver Chipset

phy0 wlan0 brcmfmac Broadcom 43430 phy1 wlan1 rtl88xxau_ohd TP-Link RTL8812AU Archer T4U 802.11ac (mac80211 monitor mode already enabled for [phy1]wlan1 on [phy1]10)

kku@rpi4:~/src/esp32-cam-fpv/gs $ iw wlan1 info Interface wlan1 ifindex 4 wdev 0x100000001 addr c4:e9:84:09:07:35 type monitor wiphy 1 channel 10 (2457 MHz), width: 20 MHz, center1: 2457 MHz txpower 18.00 dBm kku@rpi4:~/src/esp32-cam-fpv/gs $ sudo tcpdump --monitor-mode -i wlan1 tcpdump: wlan1: That device doesn't support monitor mode kku@rpi4:~/src/esp32-cam-fpv/gs $ sudo -E DISPLAY=:0 ./gs width:1280 height:720 (I) src/Comms.cpp: 723: Radiocap header size: 11, IEEE header size: 24 (I) src/Comms.cpp: 583: Opening interface wlan1 in monitor mode (E) src/Comms.cpp: 628: Error in pcap_activate: That device doesn't support monitor mode

[RomanLut]

sudo airmon-ng start wlan1 should create another interface wlan1mon with monitoring support.

But it seems that you are using some special drivers.

1) Just try to remove that check from comms.cpp

2) if it does not help, I think you have to build GS image with another drivers, you can follow these steps: https://github.com/RomanLut/esp32-cam-fpv/blob/master/doc/building_gs_image.md

[krzysztofkuczek]

Thank you, now it works, but the esp32s3sense is f... hot. Even with quite big heat sink it's hot. It draws 338mAm at 5V. Any idea? Kris

[RomanLut]

I am powering it with 4.5V on a plane, it hot but it work so far :) You can try lowering voltage up to 4V on VUSB pin: https://files.seeedstudio.com/wiki/SeeedStudio-XIAO-ESP32S3/res/XIAO_ESP32S3_SCH_v1.1.pdf

[krzysztofkuczek]

Already tried, the below 4v, the camera module seems to have some problems, showing green horizontal line, and the current is risings, U * I seems to be constant ;) So it seems to be not related to LDO voltage drop... Thank you. Kris

[krzysztofkuczek]

One More question, I was trying to move from rpi4 to rpi 0 2w, compiled everything from scratch, but without success. The wlan1 is opened correctly, but no single frame received. Any hints?

[RomanLut]

Are you compiling this branch: https://github.com/RomanLut/esp32-cam-fpv/tree/release ?

[krzysztofkuczek]

Yes, i do, according to https://github.com/RomanLut/esp32-cam-fpv/blob/master/doc/building_gs_image.md I was thinking that it's may be connected to some power issue, but the WiFi is working fine, and a power supply is 3Amps so it should be ok.

[RomanLut]

1) I assume you compile both GS and esp32cam firmware from the same branch.

2) Check serial output on air unit, you should see something like this:

WLAN S: 738000, R: 210, E: 0, F: 0, D: 0, % : 18...37 || FPS: 29, D: 331624 || SD D: 327680, E: 0 || TLM IN: 0 OUT: 0 || SK1: 100 SK2: 100, SK3: 42, Q: 23 s: 12434
WLAN S: 792612, R: 210, E: 0, F: 0, D: 0, % : 18...39 || FPS: 30, D: 362635 || SD D: 360448, E: 0 || TLM IN: 0 OUT: 0 || SK1: 100 SK2: 100, SK3: 41, Q: 24 s: 13090
WLAN S: 692244, R: 210, E: 0, F: 0, D: 0, % : 18...37 || FPS: 29, D: 314430 || SD D: 315392, E: 0 || TLM IN: 0 OUT: 0 || SK1: 100 SK2: 100, SK3: 33, Q: 29 s: 12288
WLAN S: 712908, R: 210, E: 0, F: 0, D: 0, % : 2...19 || FPS: 29, D: 326076 || SD D: 323584, E: 0 || TLM IN: 0 OUT: 0 || SK1: 100 SK2: 100, SK3: 41, Q: 24 s: 11330
WLAN S: 777852, R: 210, E: 0, F: 0, D: 0, % : 9...30 || FPS: 29, D: 355329 || SD D: 352256, E: 0 || TLM IN: 0 OUT: 0 || SK1: 100 SK2: 100, SK3: 48, Q: 20 s: 12321
WLAN S: 746856, R: 140, E: 0, F: 0, D: 0, % : 53...65 || FPS: 29, D: 348752 || SD D: 348160, E: 0 || TLM IN: 0 OUT: 0 || SK1: 100 SK2: 100, SK3: 1, Q: 60 s: 13991

FPS:29 means that camera actually works.

2) Bring debug interface with middle mouse button or d key:

FPS: 27/2 in the tille means that 27 frames was decoded and 2 was lost due to packet loss.

Do you see any numbers in the FPS: line? What is RSSI value ?