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    SubjectRe: [PATCHv2 0/3] clocksource: add db8500 PRCMU timer
    On Thu, Jun 02, 2011 at 11:34:31AM +0200, Mattias Wallin wrote:
    > The Multi Timer Unit (MTU) is currently used as clocksource and sched_clk
    > for the u8500 machine. The MTU block loose power during cpuidle sleep states
    > so an alternate clocksource is needed and these patches adds the db8500 PRCMU
    > timer.

    Why don't we just find a way of fixing sched_clock so that the value
    doesn't reset over a suspend/resume cycle? IOW, lets fix the problem
    for _everyone_ rather than only fixing it for one platform at a time.

    Could you try this patch to check whether sched_clock() behaves better
    across a suspend/resume cycle please?

    arch/arm/kernel/sched_clock.c | 18 ++++++++++++++++++
    1 files changed, 18 insertions(+), 0 deletions(-)

    diff --git a/arch/arm/kernel/sched_clock.c b/arch/arm/kernel/sched_clock.c
    index 9a46370..4be4019 100644
    --- a/arch/arm/kernel/sched_clock.c
    +++ b/arch/arm/kernel/sched_clock.c
    @@ -10,6 +10,7 @@
    #include <linux/jiffies.h>
    #include <linux/kernel.h>
    #include <linux/sched.h>
    +#include <linux/syscore_ops.h>
    #include <linux/timer.h>

    #include <asm/sched_clock.h>
    @@ -72,3 +73,20 @@ void __init sched_clock_postinit(void)
    {
    sched_clock_poll(sched_clock_timer.data);
    }
    +
    +static int sched_clock_suspend(void)
    +{
    + sched_clock_poll(sched_clock_timer.data);
    + return 0;
    +}
    +
    +static struct syscore_ops sched_clock_ops = {
    + .suspend = sched_clock_suspend,
    +};
    +
    +static int __init sched_clock_syscore_init(void)
    +{
    + register_syscore_ops(&sched_clock_ops);
    + return 0;
    +}
    +device_initcall(sched_clock_syscore_init);

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