[LinuxPPS] Confused by "line discipline support"

[Rodolfo Giometti]

On Thu, Jun 12, 2008 at 02:52:36PM -0600, 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?

The line discipline may affect the serial device usage, of course, but
PPS one should not... apart possible bugs! :)

> 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.

I'll check these stuff as soon as possible but if you see file
drivers/char/tty_io.c at function tty_ioctl() you can see that all
serial port setting are executed and only at the end of the function
the line discipline is called.

Ciao,

Rodolfo

-- 

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