QGC connection issue via type-c cable

QGroundControl
1

I have Pixhawk 6x pro connected via a Type-C cable showing /dev/ttyACM0. I added in COM-LINK in QGC. QGC is connected for an instance and disconnected again

Following is the output of the terminal

mubashir@dell:~/Downloads$ ./QGroundControl.AppImage 
Settings location "/home/mubashir/.config/QGroundControl.org/QGroundControl.ini" Is writable?: true
Filter rules "*Log.debug=false\nGStreamerAPILog.debug=true\nqt.qml.connections=false"
System reported locale: QLocale(English, Latin, United States) ; Name "en_US" ; Preffered (used in maps):  "en-US"
VideoReceiverLog: Stop called on empty URI
VideoReceiverLog: Stop called on empty URI
MAVLinkLogManagerLog: MAVLink logs directory: "/home/mubashir/Documents/QGroundControl/Logs"
Map Cache in: "/home/mubashir/.cache/QGCMapCache300" / "qgcMapCache.db"
qrc:/qml/QGroundControl/Controls/MainToolBar.qml:118:5: QML Image: Error decoding: file://home/mubashir/Downloads/warp-terminal_0.2025.04.02.08.11.stable.03_amd64.deb: Unsupported image format
setCurrentPlanViewSeqNum
setCurrentPlanViewSeqNum
"v5.0.7"
qml: clicked SerialConfiguration(0x55b6a886a020) null
 I checked on another laptop, and it is working fine. I checked the udev rules, and nothing seems wrong. I try reinstalling `QGC` multiple times

QGC version v.4.4.3
OS ubuntu-20.04 LTS

Screenshot from 2025-09-22 19-07-29
Screenshot from 2025-09-22 19-07-291277×573 73.6 KB

Screenshot from 2025-09-22 19-09-27
Screenshot from 2025-09-22 19-09-271276×576 379 KB

2

It is most likely linked to your OS or perhaps cable.

I’m running Kubuntu 24.04 and have no problem connecting.

I always connect the cable first to my Pixhawk 6X and computer, then start QGC and without needing any connection settings it will connect straight away.

Also you might try latest stable version QGC 5.0.7

3

I have a dual boot. I checked the same configuration with Windows, with the latest version of qgc, and it is working fine. I think the problem is on the OS side. but not sure what it is. I ask deep seek and gpt, which all refer to permissions /dev/ttyACM* /dev/ttyUSB* and to cable check

4

Maybe this interferes with qgc autoconnect? I guess if you specify the comm link manually autoconnect for pixhawk should be disabled? The autoconnect usually works fine for me though, never tried to configure a comm link for USB.

5

yes it autoconnect. but when not you have to look the serial connection /dev/ttyACM0 or /dev/ttyUSB0 and then add in com-link. /dev/ttyACM* show when you connect flight controller via typec-c cable. if you use FTDI cable you also need to set baudrate when it is not auto connect