[PATCH] ARM: smp: Allow real broadcast device selection instead of always dummy
tglx at linutronix.de
Thu Mar 14 04:50:17 EDT 2013
On Thu, 14 Mar 2013, Santosh Shilimkar wrote:
> On Wednesday 13 March 2013 09:48 PM, Mark Rutland wrote:
> > On Wed, Mar 13, 2013 at 03:44:03PM +0000, Santosh Shilimkar wrote:
> >> On Wednesday 13 March 2013 05:55 PM, Mark Rutland wrote:
> >>> On Wed, Mar 13, 2013 at 11:24:01AM +0000, Santosh Shilimkar wrote:
> >>>> On Wednesday 13 March 2013 03:46 PM, Mark Rutland wrote:
> >>>>> Hi Santosh,
> >> [..]
> >>>>> Is the problem that the dummy timer is being registered as the broadcast
> >>>>> source, or that it is selected as a local timer in preference of real timers?
> >>>> Dummy timer is preferred over real broadcast timer.
> >>> Ok.
> > [...]
> >>> I do agree it'd be worth lowering the dummy timer's rating to ensure it doesn't
> >>> override a real timer elsewhere.
> >> Yep. Can I add you acked-by tag then for $subject patch ?
> >> Would be good to get this one merged as well.
> > Sure. Though could you reword the commit message? The patch solves the more
> > general issue of a dummy being preferred over real hardware even outside of
> > choosing the broadcast device.
> > Acked-by: Mark Rutland <mark.rutland at arm.com>
> Thanks. For record, patch is in end of the email which I plan
> to put into patch system.
> >From 57c501bcdc88c7ff26a5c63956be07e94a5083c5 Mon Sep 17 00:00:00 2001
> From: Santosh Shilimkar <santosh.shilimkar at ti.com>
> Date: Wed, 13 Mar 2013 12:33:16 +0530
> Subject: [PATCH 1/2] ARM: smp: Avoid dummy clockevent being preferred over real hardware clock-event
> With recent arm broadcast time clean-up from Mark Rutland, the dummy
> broadcast device is always registered with timer subsystem. And since
> the rating of the dummy clock event is very high, it may be preferred
> over a real clock event.
> This is a change in behavior from past and not an intended
> one. So reduce the rating of the dummy clockevent so that
> real clockevent device is selected when available.
> Acked-by: Mark Rutland <mark.rutland at arm.com>
Acked-by: Thomas Gleixner <tglx at linutronix.de>
> Signed-off-by: Santosh Shilimkar <santosh.shilimkar at ti.com>
> arch/arm/kernel/smp.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
> diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
> index 31644f1..79078ed 100644
> --- a/arch/arm/kernel/smp.c
> +++ b/arch/arm/kernel/smp.c
> @@ -480,7 +480,7 @@ static void __cpuinit broadcast_timer_setup(struct clock_event_device *evt)
> evt->features = CLOCK_EVT_FEAT_ONESHOT |
> CLOCK_EVT_FEAT_PERIODIC |
> - evt->rating = 400;
> + evt->rating = 100;
> evt->mult = 1;
> evt->set_mode = broadcast_timer_set_mode;
More information about the linux-arm-kernel