Re: [PATCH] fix RTC_CLASS regression with PARISC

Randy.Dunlap
2008-09-10T21:09:46Z

On Wed, 10 Sep 2008, Andrew Morton wrote:

> On Mon, 08 Sep 2008 19:52:35 -0700 (PDT)
> David Miller <davem@davemloft.net> wrote:
>
> > From: David Brownell <david-b@pacbell.net>
> > Date: Mon, 8 Sep 2008 17:55:25 -0700
> >
> > > On Monday 08 September 2008, David Miller wrote:
> > > > From: David Brownell <david-b@pacbell.net>
> > > > Date: Mon, 8 Sep 2008 16:29:20 -0700
> > > >
> > > > > That said, there's a bit of unresolved stuff around NTP hooks
> > > > > in the kernel. Some patches are pending to let thtem work with
> > > > > the RTC framework -- where writing an RTC may need to sleep,
> > > > > for example because the RTC is on an I2C or SPI bus. And
> > > > > then there's the discussion of whether that shouldn't all be
> > > > > handled by NTPD anyway, no special kernel support desired.
> > > > > Alessandro has opinions there. ;)
> > > >
> > > > My update_persistent_clock() on sparc64 is:
> > > >
> > > > int update_persistent_clock(struct timespec now)
> > > > {
> > > > struct rtc_device *rtc = rtc_class_open("rtc0");
> > >
> > > I'd be tempted to cache that ... notice how you never
> > > close it, too. That will goof lots of refcounts...
> >
> > Well if I cache it then we'll hold it forever and that's not
> > so nice right?
> >
> > I'm going to put the missing rtc_close() in there for now to
> > fix the leak.
> >
> > I'm happy to cache this if you think it's warranted, but then
> > this is like saying that the refcount doesn't matter :-)
> >
> > > =============== CUT ON THE DOTTED LINE ==================
> > > Subject: ntp: let update_persistent_clock() sleep
> > > From: "Maciej W. Rozycki" <macro@linux-mips.org>
> >
> > I see, as Paul mentioned this is needed for stuff like RTCs
> > behind I2C.
> >
> > This change isn't in Linus's tree yet.
>
> Should it be?
>
> Its current status is: stuck in -mm. I've sent it to Thomas a couple
> of times marked "for 2.6.27?" and he might have applied it now (I'm a
> few days behind, waiting for linux-next to start up again).

This is something that you can attempt (again) to address next week along
with other process issues...

Maybe travel time/delay is also involved (for people other than Mr. Rothwell).

> It was not included in Thomas's recent mainline pull request:
>
> From: Thomas Gleixner <tglx@tglx.de>
> Subject: [GIT pull] timer updates for 2.6.27
> Date: Tue, 9 Sep 2008 22:32:39 +0200 (CEST)

--
~Randy