Hello,
I had the same issue, no Arduino board detected by the system, running Linux Mint 21.0 XFCE with Arduino IDE v2 and an Arduino Uno board. I had joined the Dialout group as instructed (https://support.arduino.cc/hc/en-us/articles/360016495679-Fix-port-access-on-Linux).
BRLTTY - mentioned above - was the cause of the problem, once it was removed all worked as it should.
As a Linux newbie I think the detail of the fix might be of use to someone:
- Connect your Arduino to a USB port
- in Terminal type: ls /dev
A long list of devices will appear. Look for ttyACMx or ttyUSBx [ x will be a number, for example ttyACM0 ].
If you don't find anything like that it shows that your system has not loaded the board. - In Terminal type: dmesg
A very long list of Kernel-related information will appear. Look for information about your USB ports that looks like the following:
[ 8831.372900] ch341 1-6:1.0: ch341-uart converter detected
[ 8831.374994] usb 1-6: ch341-uart converter now attached to ttyUSB0
[ 8831.421366] input: PC Speaker as /devices/platform/pcspkr/input/input27
[ 8831.964820] input: BRLTTY 6.4 Linux Screen Driver Keyboard as /devices/virtual/input/input28
[ 8832.095593] usb 1-6: usbfs: interface 0 claimed by ch341 while 'brltty' sets config #1
[ 8832.100489] ch341-uart ttyUSB0: ch341-uart converter now disconnected from ttyUSB0
[ 8832.100615] ch341 1-6:1.0: device disconnected
This shows that the system detected the board and attached it to USB0, then loaded BRLTTY utility. BRLTTY claimed the interface and subsequently the board was disconnected.
BRLTTY is an accessibility utility for blind people. If you do not need it, you can remove it from your system, together with its not needed dependent packages, by typing in Terminal: sudo apt-get remove --auto-remove brltty
Unplug and replug your board, type again in Terminal: ls /dev
If all goes to plan you should now see a ttyUSBx or ttyACMx, and your Arduino IDE show the port.