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From: David Gibson <david@gibson.dropbear.id.au>
To: Paul Mackerras <paulus@samba.org>
Cc: Daniel Walker <dwalker@mvista.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Realtime Kernel <linux-rt-users@vger.kernel.org>,
	linuxppc-dev@ozlabs.org
Subject: Re: [PATCH v2 2/4] Implement generic time of day clocksource for powerpc machines.
Date: Fri, 21 Sep 2007 16:43:21 +1000	[thread overview]
Message-ID: <20070921064321.GA13740@localhost.localdomain> (raw)
In-Reply-To: <18163.20403.967082.774118@cargo.ozlabs.ibm.com>

On Fri, Sep 21, 2007 at 02:59:31PM +1000, Paul Mackerras wrote:
> Daniel Walker writes:
> 
> > I don't think the RTC frequency isn't the same as the timebase? Seems
> > like the RTC only case about seconds at the lowest level. If that's the
> > case then the jiffies clock might be better to use .. The other thing I
> > wonder is if the __USE_RTC boards might have lower level clocks that
> > could be used instead ..
> 
> It's OK, the RTC isn't what you think it is, it's a pair of
> CPU-internal registers which count seconds and nanoseconds.  On
> processors with the RTC, tb_ticks_per_sec is initialized to
> 1000000000.  Trust me, this code is OK. :)

Indeed..  I'm wondering if we should do a s/rtc/ppc601rtc/ or
something.  Otherwise people will keep making this mistake and be
confused.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

  reply	other threads:[~2007-09-21  6:43 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-09-21  3:26 [PATCH v2 1/4] Implement {read,update}_persistent_clock Tony Breeds
2007-09-21  3:26 ` [PATCH v2 2/4] Implement generic time of day clocksource for powerpc machines Tony Breeds
2007-09-21  4:05   ` Daniel Walker
2007-09-21  4:59     ` Paul Mackerras
2007-09-21  6:43       ` David Gibson [this message]
2007-09-21  4:52   ` Stephen Rothwell
2007-09-21 21:35     ` Tony Breeds
2007-09-21 21:35     ` [PATCH v3 " Tony Breeds
2007-10-03  0:48       ` Paul Mackerras
2007-10-03  4:00         ` Thomas Gleixner
2007-09-21  3:26 ` [PATCH v2 4/4] Enable tickless idle and high res timers for powerpc Tony Breeds
2007-09-21  3:26 ` [PATCH v2 3/4] Implement clockevents driver " Tony Breeds
2007-10-15 17:40   ` Sergei Shtylyov
2007-10-15 18:33     ` Sergei Shtylyov
2007-10-15 23:44     ` Paul Mackerras
2007-10-17 14:29       ` Sergei Shtylyov
2007-10-18  0:51         ` Paul Mackerras
2007-10-18 15:11           ` Sergei Shtylyov
2007-10-19  1:53             ` Paul Mackerras
2007-10-19 12:11               ` Sergei Shtylyov
2007-10-19 12:36                 ` Paul Mackerras
2007-10-19 13:35                   ` Sergei Shtylyov
2007-10-24 12:07                     ` Sergei Shtylyov
2007-10-24 23:55                       ` Paul Mackerras
2007-10-17 14:34       ` Sergei Shtylyov
2007-10-18  0:36         ` Paul Mackerras
2007-10-18 14:48           ` Sergei Shtylyov
2007-10-19  0:14             ` Paul Mackerras
2007-10-19  9:22               ` Gabriel Paubert
2007-10-19 11:22                 ` Paul Mackerras
2007-10-19 11:49               ` Sergei Shtylyov
2007-10-19 12:24                 ` Paul Mackerras
2007-09-26 19:04 ` [PATCH v2 1/4] Implement {read,update}_persistent_clock Steven Rostedt
2007-09-26 19:39   ` Sergei Shtylyov
2007-09-26 19:44     ` Steven Rostedt
2007-09-26 19:58       ` Thomas Gleixner
2007-10-15 18:05         ` Sergei Shtylyov
2007-10-15 23:46           ` Paul Mackerras
2007-10-16  1:19           ` Benjamin Herrenschmidt
2007-10-17 12:45             ` Sergei Shtylyov
2007-09-27  1:59     ` Benjamin Herrenschmidt
2007-10-15 18:07       ` Sergei Shtylyov
2007-10-15 23:02         ` Benjamin Herrenschmidt
2007-10-17 15:34 ` Sergei Shtylyov
2007-10-18 14:18   ` Sergei Shtylyov

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