linux-kernel - Re: [PATCH v5 2/3] ARM: rockchip: ensure CPU to enter WFI/WFE state

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Date:	Tue, 09 Jun 2015 08:40:12 +0800
From:	Caesar Wang <wxt@...k-chips.com>
To:	Russell King - ARM Linux <linux@....linux.org.uk>
CC:	Heiko Stuebner <heiko@...ech.de>, dianders@...omium.org,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	linux-rockchip@...ts.infradead.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 2/3] ARM: rockchip: ensure CPU to enter WFI/WFE state



在 2015年06月08日 17:28, Russell King - ARM Linux 写道:
> On Mon, Jun 08, 2015 at 03:11:35PM +0800, Caesar Wang wrote:
>> diff --git a/arch/arm/mach-rockchip/platsmp.c b/arch/arm/mach-rockchip/platsmp.c
>> index bd40852..5bc2a89 100644
>> --- a/arch/arm/mach-rockchip/platsmp.c
>> +++ b/arch/arm/mach-rockchip/platsmp.c
>> @@ -321,6 +321,9 @@ static void __init rockchip_smp_prepare_cpus(unsigned int max_cpus)
>>   #ifdef CONFIG_HOTPLUG_CPU
>>   static int rockchip_cpu_kill(unsigned int cpu)
>>   {
>> +	/* ensure CPU can enter the WFI/WFE state */
> I would like to see a better comment here, describing what the problem
> is.  Maybe something like this:
>
> 	/*
> 	 * We need a delay here to ensure that the dying CPU can finish
> 	 * executing v7_coherency_exit() and reach the WFI/WFE state
> 	 * prior to having the power domain disabled.
> 	 */
>
> Thanks.

OK,
Thanks!
>> +	mdelay(1);
>> +
>>   	pmu_set_power_domain(0 + cpu, false);
>>   	return 1;
>>   }
>> -- 
>> 1.9.1
>>

-- 
Thanks,
- Caesar


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