Re: [PATCHv6 00/16] pps: several fixes and improvements

Andrew Morton
2010-12-18T01:15:33Z

On Sat, 18 Dec 2010 04:00:01 +0300
Alexander Gordeev <lasaine@lvk.cs.msu.su> wrote:

> __ Fri, 17 Dec 2010 16:19:38 -0800
> Andrew Morton <akpm@linux-foundation.org> __________:
>
> > On Fri, 17 Dec 2010 22:54:24 +0300
> > Alexander Gordeev <lasaine@lvk.cs.msu.su> wrote:
> >
> > > There is one problem however: kernel consumer works bad (if enabled)
> > > when CONFIG_NO_HZ is enabled. The reason for this is commit
> > > a092ff0f90cae22b2ac8028ecd2c6f6c1a9e4601. Without it hardpps() is able
> > > to sync to 1us precision in about 10 seconds. With CONFIG_NO_HZ it is
> > > not syncing at all. This only affects patches 12-14, others are ok.
> >
> > Is someone working on fixing all this?
>
> Not right now but it is planned. I can only ensure that users can never
> select CONFIG_NO_HZ and CONFIG_NTP_PPS at the same time. Is it ok?

That's much better than permitting a subtly broken driver.

CONFIG_NO_HZ is pretty common nowadays, methinks.