Restart ttyUSB or linux usb to serial force stop

Simple steps

modprobe -r ch341modprobe -r usbserialmodprobe ch341

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explanation...

The below seems to solve my problem, but not always.

1. Find the driver associated to your ttyUSBx device.

   [my-pc]# cat /proc/tty/drivers

   /dev/tty             /dev/tty        5       0 system:/dev/tty
   /dev/console         /dev/console    5       1 system:console
   /dev/ptmx            /dev/ptmx       5       2 system
   /dev/vc/0            /dev/vc/0       4       0 system:vtmaster
   rfcomm               /dev/rfcomm   216 0-255 serial
   usbserial            /dev/ttyUSB   188 0-253 serial
   ttyprintk            /dev/ttyprintk   5       3 console
   serial               /dev/ttyS       4 64-111 serial
   pty_slave            /dev/pts      136 0-1048575 pty:slave
   pty_master           /dev/ptm      128 0-1048575 pty:master
   unknown              /dev/tty        4 1-63 console
   

   You can see that /dev/ttyUSB uses usbserial. Now dig a little further:

   [my-pc]# lsmod | grep usbserial

     usbserial              37173  1 pl2303
   

   In my case, my USB-to-serial converter is a Prolific PL2303. If you have a FTDI adapter, I think you should see ftdi_sio instead of pl2303.
2. Unload the driver

   sudo modprobe -r pl2303 #or the name that matches your config

   sudo modprobe -r usbserial

3. Re-load the driver

   sudo modprobe pl2303 #or the name that matches your config

4. Re-launch your serial communication