[PATCH] ARM: smp: Allow real broadcast device selection instead of always dummy

On Wednesday 13 March 2013 09:48 PM, Mark Rutland wrote:

On Wed, Mar 13, 2013 at 03:44:03PM +0000, Santosh Shilimkar wrote:

quoted

On Wednesday 13 March 2013 05:55 PM, Mark Rutland wrote:

quoted

On Wed, Mar 13, 2013 at 11:24:01AM +0000, Santosh Shilimkar wrote:

quoted

On Wednesday 13 March 2013 03:46 PM, Mark Rutland wrote:

quoted

Hi Santosh,

[..]

quoted

quoted

quoted

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.

[...]

quoted

quoted

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@arm.com>

Thanks. For record, patch is in end of the email which I plan
to put into patch system.

Regards,
Santosh

From 57c501bcdc88c7ff26a5c63956be07e94a5083c5 Mon Sep 17 00:00:00 2001

From: Santosh Shilimkar <redacted>
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@arm.com>
Signed-off-by: Santosh Shilimkar <redacted>
---
 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 |
 			  CLOCK_EVT_FEAT_DUMMY;
-	evt->rating	= 400;
+	evt->rating	= 100;
 	evt->mult	= 1;
 	evt->set_mode	= broadcast_timer_set_mode;
 

-- 
1.7.9.5