Commit 557aaa7ffab6 ("ft232: support the ASYNC_LOW_LATENCY flag") enables unprivileged users to set the FTDI latency timer, but there was a logic flaw that skipped sending the corresponding USB control message to the device. Signed-off-by: Anthony Mallet <anthony.mallet@xxxxxxx> --- Here is the patch, feel free to update the message and/or replace the Signed-off-by if you like. Best, Anthony --- drivers/usb/serial/ftdi_sio.c~ 2017-04-28 11:20:30.339227000 +0200 +++ drivers/usb/serial/ftdi_sio.c 2017-04-28 11:20:52.647773000 +0200 @@ -1505,9 +1505,9 @@ static int set_serial_info(struct tty_st (new_serial.flags & ASYNC_FLAGS)); priv->custom_divisor = new_serial.custom_divisor; +check_and_exit: write_latency_timer(port); -check_and_exit: if ((old_priv.flags & ASYNC_SPD_MASK) != (priv->flags & ASYNC_SPD_MASK)) { if ((priv->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI) -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html