From mboxrd@z Thu Jan  1 00:00:00 1970
From: linux@arm.linux.org.uk (Russell King - ARM Linux)
Date: Tue, 10 Apr 2012 10:29:04 +0100
Subject: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to
 check presence of 32k timer
In-Reply-To: <4F83F600.4000002@ti.com>
References: <79CD15C6BA57404B839C016229A409A83184846A@DBDE01.ent.ti.com>
 <20120405095221.GC25053@n2100.arm.linux.org.uk>
 <79CD15C6BA57404B839C016229A409A831848621@DBDE01.ent.ti.com>
 <87hawxkgoi.fsf@ti.com>
 <79CD15C6BA57404B839C016229A409A831849432@DBDE01.ent.ti.com>
 <20120406180452.GB15734@atomide.com>
 <79CD15C6BA57404B839C016229A409A83184ABEF@DBDE01.ent.ti.com>
 <4F83440E.70502@ti.com> <20120410084413.GD25053@n2100.arm.linux.org.uk>
 <4F83F600.4000002@ti.com>
Message-ID: <20120410092904.GE25053@n2100.arm.linux.org.uk>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Tue, Apr 10, 2012 at 02:27:36PM +0530, Santosh Shilimkar wrote:
> On Tuesday 10 April 2012 02:14 PM, Russell King - ARM Linux wrote:
> > On Mon, Apr 09, 2012 at 03:18:22PM -0500, Jon Hunter wrote:
> >> True, but we would always want to use the 32k timer if CONFIG_PM is  
> >> specified. So what I am saying is that if a device has a 32ksync timer  
> >> and CONFIG_PM is defined, we always want to use the 32ksync timer and a  
> >> gptimer should never be used.
> > 
> > Why?  What if you want to have PM enabled, and you also want to use the
> > kernels high resolution timers, or you want more accurate timing than
> > the 30.5us tick interval of the 32k timer?
> 
> You might have missed the earlier comments on the thread. High
> resolution GP timer(sysclk) will stop in deeper power states and
> hence it can't be used with PM enabled usecases.

Which means folk should be given the choice at boot time between running
with the deeper power states and having a higher resolution timing source,
rather than denying them the higher resolution timing source when PM is
enabled.