From b1f919664d04a8d0ba29cb76673c7ca3325a2006 Mon Sep 17 00:00:00 2001 From: "Yang Honggang (Joseph)" Date: Thu, 1 Dec 2011 22:22:41 -0500 Subject: clocksource: Fix bug with max_deferment margin calculation In order to leave a margin of 12.5% we should >> 3 not >> 5. CC: stable@kernel.org Signed-off-by: Yang Honggang (Joseph) [jstultz: Modified commit subject] Signed-off-by: John Stultz --- kernel/time/clocksource.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/time') diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index cfc65e1eb9fb..da2f760e780c 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -548,7 +548,7 @@ static u64 clocksource_max_deferment(struct clocksource *cs) * note a margin of 12.5% is used because this can be computed with * a shift, versus say 10% which would require division. */ - return max_nsecs - (max_nsecs >> 5); + return max_nsecs - (max_nsecs >> 3); } #ifndef CONFIG_ARCH_USES_GETTIMEOFFSET @@ -669,7 +669,7 @@ void __clocksource_updatefreq_scale(struct clocksource *cs, u32 scale, u32 freq) * ~ 0.06ppm granularity for NTP. We apply the same 12.5% * margin as we do in clocksource_max_deferment() */ - sec = (cs->mask - (cs->mask >> 5)); + sec = (cs->mask - (cs->mask >> 3)); do_div(sec, freq); do_div(sec, scale); if (!sec) -- cgit v1.2.3 From c1be84309c58b1e7c6d626e28fba41a22b364c3d Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 2 Dec 2011 12:34:16 +0100 Subject: tick-broadcast: Stop active broadcast device when replacing it When a better rated broadcast device is installed, then the current active device is not disabled, which results in two running broadcast devices. Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org --- kernel/time/tick-broadcast.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/time') diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index f954282d9a82..fd4a7b1625a2 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -71,7 +71,7 @@ int tick_check_broadcast_device(struct clock_event_device *dev) (dev->features & CLOCK_EVT_FEAT_C3STOP)) return 0; - clockevents_exchange_device(NULL, dev); + clockevents_exchange_device(tick_broadcast_device.evtdev, dev); tick_broadcast_device.evtdev = dev; if (!cpumask_empty(tick_get_broadcast_mask())) tick_broadcast_start_periodic(dev); -- cgit v1.2.3 From de28f25e8244c7353abed8de0c7792f5f883588c Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 2 Dec 2011 16:02:45 +0100 Subject: clockevents: Set noop handler in clockevents_exchange_device() If a device is shutdown, then there might be a pending interrupt, which will be processed after we reenable interrupts, which causes the original handler to be run. If the old handler is the (broadcast) periodic handler the shutdown state might hang the kernel completely. Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org --- kernel/time/clockevents.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel/time') diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index 1ecd6ba36d6c..c4eb71c8b2ea 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -387,6 +387,7 @@ void clockevents_exchange_device(struct clock_event_device *old, * released list and do a notify add later. */ if (old) { + old->event_handler = clockevents_handle_noop; clockevents_set_mode(old, CLOCK_EVT_MODE_UNUSED); list_del(&old->list); list_add(&old->list, &clockevents_released); -- cgit v1.2.3