On Tue, Sep 19, 2017 at 11:44:57PM +0200, Andreas Steinmetz wrote:
> [Please CC me on replies, I'm not subscribed]
>
> There's systems around that only have incompletely wired serial ports,
> e.g. the CompuLab Intense PC3 which only has 4 wire serial ports (RxD,
> TxD, RTS, CTS).
>
> The kernel currently only supports DCD for the PPS line discipline.
>
> The attached patch adds a configuration option that allows CTS to be
> used instead of DCD for the PPS line discipline for 8250/16x50 based
> serial ports.
>
> It may look a bit ugly but it seems to me to be the least intrusive way
> to enable the use of the kernel PPS line discipline for machines with
> incompletely wired serial ports.
>
> The patch is actually against 4.12.10 (sorry for the older kernel) and
> tested with gpsd on a CompuLab Intense PC3.
> --
> Andreas Steinmetz SPAMmers use robotrap@xxxxxxxx
> --- linux.orig/drivers/tty/serial/serial_core.c 2017-09-19 22:15:00.655700355 +0200
> +++ linux/drivers/tty/serial/serial_core.c 2017-09-19 22:15:05.748732334 +0200
> @@ -2920,10 +2920,13 @@
> {
> struct tty_port *port = &uport->state->port;
> struct tty_struct *tty = port->tty;
> +#ifndef CONFIG_PPS_CLIENT_LDISC_CTS
> struct tty_ldisc *ld;
> +#endif
Ick, that's pretty bad. And probably something, if you really wanted to
do this, you should do on a per-port basis, not for all serial ports,
right?
Also, we hate #ifdef in .c code, as well as the patch not being in a
format we could apply it in, even if we liked it.
Care to fix it up to be more general purpose? Or how about just buying
better hardware? :)
thanks,
greg k-h
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