Hi, I've been using OpenWrt's "usb activity" led trigger to display usb-serial traffic over a cp210x dongle quite successfully, but after replacing the cp210x with a FT230x, I find that I get constant USB traffic (every millisecond) as soon as the port is opened. I've put a usbmon capture available here: https://github.com/karlp/ftx-linux-usb/blob/master/ftx-3.18.12.openport.idle.pcap (Captured with tcpdump -i usbmon1 -w ...., then opening the port with picocom, waiting, then exiting) This is from opening /dev/ttyUSB0 with picocom. I've added ftdio_sio module debugging, which produces the following output [ 5829.430000] ftdi_sio ttyUSB0: Setting CS8 [ 5829.430000] ftdi_sio ttyUSB0: get_ftdi_divisor - tty_get_baud_rate reports speed 19200 [ 5829.430000] ftdi_sio ttyUSB0: get_ftdi_divisor - Baud rate set to 19200 (divisor 0x809C) on chip FT-X [ 5829.430000] ftdi_sio ttyUSB0: ftdi_set_termios Turning off hardware flow control [ 5829.430000] ftdi_sio ttyUSB0: update_mctrl - DTR HIGH, RTS HIGH [ 5829.430000] ftdi_sio ttyUSB0: ftdi_get_modem_status - 0x0160 [ 5829.430000] ftdi_sio ttyUSB0: get_ftdi_divisor - tty_get_baud_rate reports speed 19200 [ 5829.430000] ftdi_sio ttyUSB0: get_ftdi_divisor - Baud rate set to 19200 (divisor 0x809C) on chip FT-X [ 5829.430000] ftdi_sio ttyUSB0: ftdi_set_termios Turning off hardware flow control <<<<< exit from picocom here >>>>> [ 5856.460000] ftdi_sio ttyUSB0: ftdi_get_modem_status - 0x0160 [ 5856.460000] ftdi_sio ttyUSB0: get_ftdi_divisor - tty_get_baud_rate reports speed 19200 [ 5856.460000] ftdi_sio ttyUSB0: get_ftdi_divisor - Baud rate set to 19200 (divisor 0x809C) on chip FT-X [ 5856.460000] ftdi_sio ttyUSB0: ftdi_set_termios Turning off hardware flow control [ 5857.520000] ftdi_sio ttyUSB0: ftdi_get_modem_status - 0x0160 It's important to note that /dev/ttyUSB0 still _works_ I just get substantially more usb traffic than I expect. I do _not_ see this level of traffic with any FT232RL devices or cp210x devices, though, unfortunately, I can't test those with the same hardware. The FT230x is permanently connected to a SMSC USB2640 hub on a custom board. I also don't have a FT230x I can try on my desktop linux either at this stage. :( This is seen with kernel 3.18.12, but was originally seen with 3.10.49. I can't see anything in the ftdio_sio driver other than new VID/PIDs since 3.18, so I haven't tried anything newer. The usbmon traces seem to be a continual reporting of the "0x0160" shown in the ftdi_get_modem_status lines. Is this actually _meant_ to be happening? Can I turn it off? Any other suggestions? Sincerely, Karl Palsson
