linux-kernel - Re: [PATCH 01/16] APM idle: register apm_cpu

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Date:	Mon, 11 Feb 2013 17:50:37 -0500
From:	Len Brown <lenb@...nel.org>
To:	Daniel Lezcano <daniel.lezcano@...aro.org>
CC:	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	Len Brown <len.brown@...el.com>, Jiri Kosina <jkosina@...e.cz>
Subject: Re: [PATCH 01/16] APM idle: register apm_cpu_idle via cpuidle

On 02/11/2013 04:18 AM, Daniel Lezcano wrote:
> On 02/10/2013 06:58 AM, Len Brown wrote:
>> From: Len Brown <len.brown@...el.com>
>>
>> Update APM to register its local idle routine with cpuidle.
>>
>> This allows us to stop exporting pm_idle to modules on x86.
>>
>> The Kconfig sub-option, APM_CPU_IDLE, now depends on on CPU_IDLE.
>>
>> Compile-tested only.
>>
>> Signed-off-by: Len Brown <len.brown@...el.com>
>> Cc: Jiri Kosina <jkosina@...e.cz>
>> ---
> 

>> +static struct cpuidle_device apm_cpuidle_device = {
>> +	.state_count = 2,
>> +};
> 
> This will make the cpuidle_register_driver to fail because the
> state_count field of the cpuidle_driver is zero, no ?
> 
> static struct cpuidle_driver apm_idle_driver = {
> 	.name = "apm_idle",
> 	...
> 	.states = {
> 	...
> 	},
> 	.state_count = 2,
> }

yup, good catch.

>> -static void apm_cpu_idle(void)
>> +static int apm_cpu_idle(struct cpuidle_device *dev,
>> +	struct cpuidle_driver *drv, int index)
>>  {
>>  	static int use_apm_idle; /* = 0 */
>>  	static unsigned int last_jiffies; /* = 0 */
...
>> @@ -964,6 +983,7 @@ recalc:
>>  		apm_do_busy();
>>  
>>  	local_irq_enable();
> 
>            ^^^^^^^^
> 
> As the 'en_core_tk_irqen' flag has been enabled in the driver, the
> caller of this function will call 'local_irq_enable'. We can remove the
> this line no ?

yup, this line is no longer necessary.

v2 on the way -- hoping somebody with an APM box can test it.

thanks,
-Len Brown, Intel Open Source Technology Center

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