Hello Greg, Pali has worked out some improvements for the ftdi_sio USB serial driver and I have tested them. Marek Pali Rohár (7): USB: serial: ftdi_sio: Fix divisor overflow USB: serial: ftdi_sio: Add missing baudrate validation USB: serial: ftdi_sio: Extract SIO divisor code to function USB: serial: ftdi_sio: Do not reset baudrate to 9600 on error USB: serial: ftdi_sio: Fix baudrate rounding for ASYNC_SPD_CUST USB: serial: ftdi_sio: Fix custom_divisor and c_*speed for ASYNC_SPD_CUST USB: serial: ftdi_sio: Fill c_*speed fields with real baudrate drivers/usb/serial/ftdi_sio.c | 181 ++++++++++++++++++++++++++++------ 1 file changed, 151 insertions(+), 30 deletions(-) -- 2.35.1