I have got a PC with Ubuntu 14.04 desktop. The main plate has a serial port (ttyS0) that works perectly, but the ports in additional PCI cards don't. When my program calls "open", this function is not returning and the program stops hanging there. If I would use the port ttyS0, the function returns and the program continues using the port transmiting information.
What could be the reason for "open" hanging. Setserial shows me that system is detecting those ports and assigning IRQ's.
Could you help me? Do you know any link where I could see for help?