Re: [PATCH] timer TSC check suspend notifier change

From: Andi Kleen
Date: Tue May 02 2006 - 02:36:59 EST


Shaohua Li <shaohua.li@xxxxxxxxx> writes:

> in suspend time, the TSC CPUFREQ_SUSPENDCHANGE notifier change might wrongly
> enable interrupt. cpufreq driver suspend/resume is in interrupt disabled environment.
>
> Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx>
> ---
>
> linux-2.6.17-rc3-root/arch/i386/kernel/timers/timer_tsc.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff -puN arch/i386/kernel/timers/timer_tsc.c~timer_tsc_check_suspend_change arch/i386/kernel/timers/timer_tsc.c
> --- linux-2.6.17-rc3/arch/i386/kernel/timers/timer_tsc.c~timer_tsc_check_suspend_change 2006-04-29 08:25:38.000000000 +0800
> +++ linux-2.6.17-rc3-root/arch/i386/kernel/timers/timer_tsc.c 2006-04-29 08:29:33.000000000 +0800
> @@ -279,7 +279,7 @@ time_cpufreq_notifier(struct notifier_bl
> {
> struct cpufreq_freqs *freq = data;
>
> - if (val != CPUFREQ_RESUMECHANGE)
> + if (val != CPUFREQ_RESUMECHANGE && val != CPUFREQ_SUSPENDCHANGE)
> write_seqlock_irq(&xtime_lock);

Better would be to change it to write_seqlock_irqsave() (if that
exists, if not add it)


> if (!ref_freq) {
> if (!freq->old){
> @@ -312,7 +312,7 @@ time_cpufreq_notifier(struct notifier_bl
> }
>
> end:
> - if (val != CPUFREQ_RESUMECHANGE)
> + if (val != CPUFREQ_RESUMECHANGE && val != CPUFREQ_SUSPENDCHANGE)
> write_sequnlock_irq(&xtime_lock);

and _restore

-Andi
-
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