Hi all, I'm trying to set up a serial port on our industrial PC board to run at 500kbps baudrate. According to the board manufacturer it should be possible but I keep failing. The board is RTD CMX158886 cpu module with SMSC SCH3116 SuperIO chip providing two serial ports. At 115200 I can feed data into /dev/ttyS0 at roughly 10kB/s which is expected. But I have never achieved anything better than this. First I tried setserial with all different combinations of options (including spd_cust, baud_base and divisor setting) but either they didn't make any difference or made the port slower. Then I wrote a simple kernel module for setting the UART parameters directly on the SuperIO chip - one of its registers is supposed to switch it to faster input clock and thus allow up to 1.5Mbps baudrate. But again all my attempts either seemed ignored by the system or made things even worse. Finally I found some hints about setting "tty->termios->c_cflag speed to B38400 and the desired baudrate be in tty->alt_speed". Here 'tty' is apparently of 'struct tty_struct' type, but I haven't found how to retrieve the current tty_struct for a port and how to set it back. All I found are tcgetattr() and tcsetattr() functions but these seem to provide only 'struct termios', not the parent struct tty_struct. I understand that support for non-standard baudrates is hw-dependent, however our HW should support them. I just don't know how to turn it on. Do you have any hints? Either through kernel module or user space? Thanks! Michal -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
