I recently bought a esp32 devkit with ch340 USB-UART bridge.
After plugging it into the USB port of my Ubuntu 22.04 the serial port
/dev/ttyUSB0 repeatedly connects and disconnects.
Also, I have tried this on Windows and Fedora where it worked as expected, so I think it might be a Ubuntu related issue.
[ 662.091302] usb 1-2: new full-speed USB device number 117 using xhci_hcd [ 662.253355] usb 1-2: New USB device found, idVendor=1a86, idProduct=7523, bcdDevice=81.33 [ 662.253366] usb 1-2: New USB device strings: Mfr=0, Product=2, SerialNumber=0 [ 662.253370] usb 1-2: Product: USB Serial [ 662.258186] ch341 1-2:1.0: ch341-uart converter detected [ 662.272620] usb 1-2: ch341-uart converter now attached to ttyUSB0 [ 665.739336] usb 1-2: USB disconnect, device number 117 [ 665.739737] ch341-uart ttyUSB0: ch341-uart converter now disconnected from ttyUSB0 [ 665.739770] ch341 1-2:1.0: device disconnected
tail -f /var/log/syslog shows two additional lines:
checking bus 1, device 125: "/sys/devices/pci0000:00/0000:00:08.1/0000:05:00.3/usb1/1-2" bus: 1, device: 125 was not an MTP device
- disabling autosuspend with
udevrules as described in arch wiki (I'm not sure why this doesn't work)
- disabling autosuspend by changing
on(the file is set back to
autoafter a few seconds)
- updating to the latest kernel
- debugging the driver with kprobe
Does anyone have an idea how to solve this? If I won't fix it I'll probably have to change distro, and I don't really have time to do it right now.