[PATCH] ARM: smp: Allow real broadcast device selection instead of always dummy
From: mark.rutland@arm.com (Mark Rutland)
Date: 2013-03-14 10:28:07
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linux-omap
On Thu, Mar 14, 2013 at 07:45:14AM +0000, Santosh Shilimkar wrote:
On Wednesday 13 March 2013 09:48 PM, Mark Rutland wrote:quoted
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
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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
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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
The below patch seems fine. Are you intending for this to go in as a fix for 3.9-rc*, or as a cleanup for 3.10? If you're aiming for the latter, it's going to clash with Stephen Boyd's local timer API removal [1], in which the generic dummy timer driver [2] (replacing the arm-specific dummy [3]) also has a rating of 100. It would be nice if we could reduce the possibility of a conflict. [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2013-March/154724.html [2] http://lists.infradead.org/pipermail/linux-arm-kernel/2013-March/154725.html [3] http://lists.infradead.org/pipermail/linux-arm-kernel/2013-March/154726.html Thanks, Mark.
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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