[LinuxPPS] Confused by "line discipline support"

[Cirilo Bernardo]

On Thu, Jun 12, 2008 at 8:52 PM,  <clemens at dwf.com> wrote:
> Im having problems understanding what is going on with my simple test program
> and with ntpd.
>
> So I have a question.
>
> Once we have used setctrl on /dev/ttyS0 to set the 'line discipline' (and
> create
> /dev/pps{n}) should /dev/ttyS0 still work 'as usual' or has it been affected by
> this 'line discipline' stuff too?
>
> I seem to be getting errors when I try to set /dev/ttyS0 to RAW and B9600 after
> having set the line discipline, although right now Im confused enough that I
> could be missing something simple.  I can stat the file, I just cant open it
> with
> the options that I want.
>

Perhaps there is a bug in the line discipline code?  Have a look at
drivers/net/ppp_async.c (this is the simplest line discipline that
comes to mind).  In ppp_asynctty_ioctl( )  you can see how the job is
passed on to the raw tty_ioctl layer.

- Cirilo