On 2013-09-28, Matwey V. Kornilov <matwey.kornilov@xxxxxxxxx> wrote: > 28.09.2013 21:21, Matwey V. Kornilov ?????: >> It seems that BSD and Unix98 pty's may coexist in pty.c. So, there is a >> chance that it is possible to add support of Extended pty not breaking >> existing things. One need to be a brave to change something in pty.c, It >> is quite critical part. > > It seems that we need new line discipline to allow async notification of > master tty when the client changes tty->termios. poll() has to be > reimplemented to generate POLLPRI, when tty->termios handling required > on the master side, then master may use special ioctl to read > tty->termios requested. I was thinking about initially just creating a blocking ioctl() call that the master can use to wait for either a termios configuration change or a modem control line change. I admit that's not as elegent: it would mean a master would need multiple threads in most cases (one for data and one for config and modem status). But, it may be a less intrusive change [I haven't looked at the poll implementation in any detail, so perhaps the poll change isn't as bad as I fear.] Having to use multiple threads in a master sounds ugly at first, but it's still orders of magnitude easier than implementing a serial driver in kernel space that uses network I/O to communicate with the physical UART. -- Grant -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
