[Xen-devel] Re: [PATCH] Fix cpuidle bug

[Keir Fraser <keir.xen@xxxxxxxxx>]

Is this for 4.0 and 4.1 branches as well?

 -- Keir

On 10/03/2011 08:37, "Liu, Jinsong" <jinsong.liu@xxxxxxxxx> wrote:

> Fix cpuidle bug
> 
> Before invoking C3, bus master disable / flush cache should be the last step;
> After resume from C3, bus master enable should be the first step;
> 
> Signed-off-by: Liu, Jinsong <jinsong.liu@xxxxxxxxx>
> 
> diff -r 9d6da64267ed xen/arch/x86/acpi/cpu_idle.c
> --- a/xen/arch/x86/acpi/cpu_idle.c Sun Mar 06 17:28:48 2022 +0800
> +++ b/xen/arch/x86/acpi/cpu_idle.c Mon Mar 07 05:31:46 2022 +0800
> @@ -457,6 +457,19 @@ static void acpi_processor_idle(void)
>  
>      case ACPI_STATE_C3:
>          /*
> +         * Before invoking C3, be aware that TSC/APIC timer may be
> +         * stopped by H/W. Without carefully handling of TSC/APIC stop
> issues,
> +         * deep C state can't work correctly.
> +         */
> +        /* preparing APIC stop */
> +        lapic_timer_off();
> +
> +        /* Get start time (ticks) */
> +        t1 = get_tick();
> +        /* Trace cpu idle entry */
> +        TRACE_4D(TRC_PM_IDLE_ENTRY, cx->idx, t1, exp, pred);
> +
> +        /*
>           * disable bus master
>           * bm_check implies we need ARB_DIS
>           * !bm_check implies we need cache flush
> @@ -485,20 +498,18 @@ static void acpi_processor_idle(void)
>              ACPI_FLUSH_CPU_CACHE();
>          }
>  
> -        /*
> -         * Before invoking C3, be aware that TSC/APIC timer may be
> -         * stopped by H/W. Without carefully handling of TSC/APIC stop
> issues,
> -         * deep C state can't work correctly.
> -         */
> -        /* preparing APIC stop */
> -        lapic_timer_off();
> -
> -        /* Get start time (ticks) */
> -        t1 = get_tick();
> -        /* Trace cpu idle entry */
> -        TRACE_4D(TRC_PM_IDLE_ENTRY, cx->idx, t1, exp, pred);
>          /* Invoke C3 */
>          acpi_idle_do_entry(cx);
> +
> +        if ( power->flags.bm_check && power->flags.bm_control )
> +        {
> +            /* Enable bus master arbitration */
> +            spin_lock(&c3_cpu_status.lock);
> +            acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
> +            c3_cpu_status.count--;
> +            spin_unlock(&c3_cpu_status.lock);
> +        }
> +
>          /* Get end time (ticks) */
>          t2 = get_tick();
>  
> @@ -508,15 +519,6 @@ static void acpi_processor_idle(void)
>          /* Trace cpu idle exit */
>          TRACE_6D(TRC_PM_IDLE_EXIT, cx->idx, t2,
>                   irq_traced[0], irq_traced[1], irq_traced[2], irq_traced[3]);
> -
> -        if ( power->flags.bm_check && power->flags.bm_control )
> -        {
> -            /* Enable bus master arbitration */
> -            spin_lock(&c3_cpu_status.lock);
> -            if ( c3_cpu_status.count-- == num_online_cpus() )
> -                acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
> -            spin_unlock(&c3_cpu_status.lock);
> -        }
>  
>          /* Re-enable interrupts */
>          local_irq_enable();



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