Serial Port: How to adjust serial port buffer size in kernel space

Question

I need to know how to adjust serial port buffer size in kernel space. ioctl and similar commands do not work in kernel space. I am using RTAI functions. rt_spopen, rt_spwrite else.. Reason of my wish relies on sending large packets (367 byte) over serial port (COM1) by a null modem cable.

Best

Answer 1

RTAI's serial port driver uses outb directly to write to port, and being in real-time, it has nothing to do with the Linux kernel.

The default buffer size of the module seems to be 512, but nevertheless, the spbufsiz module parameter seems to be governing this. Try setting a larger value for that. Also, make sure, maybe with an oscilloscope that you are sending enough bytes, so you'd make sure that the bug is not on the other end that can't buffer that much input.