Johan, While working on the tx_empty changes you suggested it occurred to me that it might not be obvious to others that the firmware doesn't send a packet with the NT124_CTRL_TXEMPTY flag cleared when it begins transmitting. The practical implication is that if the driver sets tx_empty = true when it sees NT124_CTRL_TXEMPTY, tx_empty must be reset to false somewhere when more data is transmitted. Perhaps I could add prepare_write_buffer and do it in there before calling usb_serial_generic_prepare_write_buffer(). Does that sound acceptable? If so I'll also initialize tx_empty = true in nt124_port_probe. Regards, George -- 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