Enable arm_global_timer for Zynq brakes boot
From: Stephen Boyd <hidden>
Date: 2013-08-09 17:28:01
Also in:
lkml
Subsystem:
nohz, dynticks support, the rest · Maintainers:
Anna-Maria Behnsen, Frederic Weisbecker, Ingo Molnar, Thomas Gleixner, Linus Torvalds
On 08/09, Daniel Lezcano wrote:
yes, but at least the broadcast mechanism should send an IPI to cpu0 to wake it up, no ? As Stephen stated this kind of configuration should has never been tested before so the tick broadcast code is not handling this case properly IMHO.
If you have a per-cpu tick device that isn't suffering from FEAT_C3_STOP why wouldn't you use that for the tick versus a per-cpu tick device that has FEAT_C3_STOP? It sounds like there is a bug in the preference logic or you should boost the rating of the arm global timer above the twd. Does this patch help? It should make the arm global timer the tick device and whatever the cadence timer you have into the broadcast device. ---8<----
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 218bcb5..d3539e5 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c@@ -77,6 +77,9 @@ static bool tick_check_broadcast_device(struct clock_event_device *curdev, !(newdev->features & CLOCK_EVT_FEAT_ONESHOT)) return false; + if (cpumask_equal(newdev->cpumask, cpumask_of(smp_processor_id()))) + return false; + return !curdev || newdev->rating > curdev->rating; }
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 64522ec..1628b9f 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c@@ -245,6 +245,15 @@ static bool tick_check_preferred(struct clock_event_device *curdev, } /* + * Prefer tick devices that don't suffer from FEAT_C3_STOP + * regardless of their rating + */ + if (curdev && cpumask_equal(curdev->cpumask, newdev->cpumask) && + !(newdev->features & CLOCK_EVT_FEAT_C3STOP) && + (curdev->features & CLOCK_EVT_FEAT_C3STOP)) + return true; + + /* * Use the higher rated one, but prefer a CPU local device with a lower * rating than a non-CPU local device */
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation