[LinuxPPS] http://lkml.org/lkml/2008/4/11/42

[Bernhard Schiffner]

Am Samstag, 19. April 2008 18:37 schrieb Rodolfo Giometti:


> Step 1) Fix up the lowlevel x86-only irq method which improve
>         resolution so much.
>
> 	This step should be easy to implement regarding the timestamp
> 	issue, a bit complicated regarding the echo function...
>
Best to do for the PPS-community.
But  I doubt you can sell it as PPS to lkml. Better to speak about 
an "interrupt-tracer" or use any other buzzword.

BUT:
PPS is already on the radar of Andrew Morton, so I think its the best to go 
the recent way as far as we can.
(And buy Alans tty->ops knowing not to be ideal, but "requested" as a step 
to pass. What happens later on: let#s be prepared. )

> Step 2) We can completely remove the PPS code from tty serial code
> 	by using a "generic" client (maybe called pps-generic-irq?)
> 	which can be used with any IRQ source.
>
> 	We can implement something that loaded as follow:
>
> 	$ modprobe pps-generic-irq.ko irqs=1,4
>
> 	enables two PPS sources linked with IRQs 1 and 4.
>
> The first step should improve resolution and the second should remove
> the problem with serial code.

No remove (now).
What is about shared interrupts?
How does NTP (as primary PPs-user) handle such an situation?

> What do you think about these solutions? :)
>
> Rodolfo

IMHO:
1.) Continue on inclusion and adapt Alans tty->ops for the serial client.
2) Improve lowlevel-irq. (but don't post to lkml)

Bernhard