On Fri, 2007-12-07 at 19:36 +0100, Ingo Molnar wrote:
> Linus, please pull the latest x86 git tree from:
> 
>    git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86.git
> 
> This contains 3 x86/hrtimer/hpet/ACPI fixes from Thomas: the ACPI fix 
> has been ACK-ed by Venki. Build and boot tested on various boxes.

Ingo, I was about to post about timer problems in 2.6.23.9+rt12 when I
saw this. Would this be related / should I test / will this solve
everything? :-)

What I'm seeing is jack "delays" that go away if I boot with
"idle=poll", just like it was happening a long time ago. Smells like
'time of day' glitches when the process switches cpus (this is on a dual
core intel laptop). 

Does not happen in 2.6.22.10 + rt9 - well, I do see very occassional
delay warnings there as well. 

I also see occassional complete hangs but I don't have a way of knowing
what triggers that. 

-- Fernando


> ------------------>
> Thomas Gleixner (3):
>       hrtimers: avoid overflow for large relative timeouts
>       clockevents: warn once when program_event() is called with negative 
> expiry
>       ACPI: move timer broadcast before busmaster disable
> 
>  drivers/acpi/processor_idle.c |   19 ++++++++++++++-----
>  kernel/hrtimer.c              |    8 ++++++++
>  kernel/time/clockevents.c     |    5 +++++
>  3 files changed, 27 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
> index b1fbee3..2fe34cc 100644
> --- a/drivers/acpi/processor_idle.c
> +++ b/drivers/acpi/processor_idle.c
> @@ -531,6 +531,11 @@ static void acpi_processor_idle(void)
>  
>       case ACPI_STATE_C3:
>               /*
> +              * Must be done before busmaster disable as we might
> +              * need to access HPET !
> +              */
> +             acpi_state_timer_broadcast(pr, cx, 1);
> +             /*
>                * disable bus master
>                * bm_check implies we need ARB_DIS
>                * !bm_check implies we need cache flush
> @@ -557,7 +562,6 @@ static void acpi_processor_idle(void)
>               /* Get start time (ticks) */
>               t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
>               /* Invoke C3 */
> -             acpi_state_timer_broadcast(pr, cx, 1);
>               /* Tell the scheduler that we are going deep-idle: */
>               sched_clock_idle_sleep_event();
>               acpi_cstate_enter(cx);
> @@ -1401,9 +1405,6 @@ static int acpi_idle_enter_simple(struct cpuidle_device 
> *dev,
>       if (acpi_idle_suspend)
>               return(acpi_idle_enter_c1(dev, state));
>  
> -     if (pr->flags.bm_check)
> -             acpi_idle_update_bm_rld(pr, cx);
> -
>       local_irq_disable();
>       current_thread_info()->status &= ~TS_POLLING;
>       /*
> @@ -1418,13 +1419,21 @@ static int acpi_idle_enter_simple(struct 
> cpuidle_device *dev,
>               return 0;
>       }
>  
> +     /*
> +      * Must be done before busmaster disable as we might need to
> +      * access HPET !
> +      */
> +     acpi_state_timer_broadcast(pr, cx, 1);
> +
> +     if (pr->flags.bm_check)
> +             acpi_idle_update_bm_rld(pr, cx);
> +
>       if (cx->type == ACPI_STATE_C3)
>               ACPI_FLUSH_CPU_CACHE();
>  
>       t1 = inl(acpi_gbl_FADT.xpm_timer_block.address);
>       /* Tell the scheduler that we are going deep-idle: */
>       sched_clock_idle_sleep_event();
> -     acpi_state_timer_broadcast(pr, cx, 1);
>       acpi_idle_do_entry(cx);
>       t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
>  
> diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
> index 22a2514..e65dd0b 100644
> --- a/kernel/hrtimer.c
> +++ b/kernel/hrtimer.c
> @@ -850,6 +850,14 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const 
> enum hrtimer_mode mode)
>  #ifdef CONFIG_TIME_LOW_RES
>               tim = ktime_add(tim, base->resolution);
>  #endif
> +             /*
> +              * Careful here: User space might have asked for a
> +              * very long sleep, so the add above might result in a
> +              * negative number, which enqueues the timer in front
> +              * of the queue.
> +              */
> +             if (tim.tv64 < 0)
> +                     tim.tv64 = KTIME_MAX;
>       }
>       timer->expires = tim;
>  
> diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
> index 822beeb..5fb139f 100644
> --- a/kernel/time/clockevents.c
> +++ b/kernel/time/clockevents.c
> @@ -78,6 +78,11 @@ int clockevents_program_event(struct clock_event_device 
> *dev, ktime_t expires,
>       unsigned long long clc;
>       int64_t delta;
>  
> +     if (unlikely(expires.tv64 < 0)) {
> +             WARN_ON_ONCE(1);
> +             return -ETIME;
> +     }
> +
>       delta = ktime_to_ns(ktime_sub(expires, now));
>  
>       if (delta <= 0)
> --
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