Re: [PATCH] OMAP3: PM: Add the wakeup source driver, v2

[Kevin Hilman <khilman@deeprootsystems.com>]

Kim Kyuwon <chammoru@gmail.com> writes:

> Hi Kevin,
> Thanks for your prompt answer.
>
> On Sat, Apr 4, 2009 at 1:12 AM, Kevin Hilman
> <khilman@deeprootsystems.com> wrote:
>> Kim Kyuwon <chammoru@gmail.com> writes:
>>
>>>>> +
>>>>> +void omap3_get_wakeup_status(struct pm_wakeup_status **pm_wkst)
>>>>> +{
>>>>> +     *pm_wkst = &omap3_pm_wkst;
>>>>> +}
>>>>> +
>>>>
>>>> Can you rename this to omap3_get_last_wake_state()
>>>
>>> Actually, I removed this function and I didn't get the WKST registers
>>> from the last PRCM interrupt in the new patch. Sorry that I don't
>>> address your suggestion. But I found that the PRCM interrupt is being
>>> generated in normal state on the latest PM branch and, from OMAP34XX
>>> TRM (4.9 PRCM Interrupts), PRCM Interrupts can be generated in many
>>> cases in addition to wake-up from suspend. So if my wakeup code gets
>>> the WSKT values from PRCM interrupt, I think it could show the wrong
>>> information.
>>>
>>
>> What type of wrong information do you think you would get?
>
> On our custom OMAP3430 ES3.1 board on which the latest PM branch
> kernel is running, the PRCM interrupt is being generated about every
> 0.5 sec.(not exact) and 'OMAP3430_ST_GPT12_MASK' is set in the
> PM_WKST_WKUP register.

Hmm, have you configured GPTIMER12 as the system timer?

> FYI: When I wrongly configured the d2d_mstdby and d2d_swakeup pads,
> PRCM interrupts was also generated (Refer to
> http://markmail.org/thread/juardvjdvsrrqwuj)
>
>> After looking again, you are probably querying the WKST registers
>> too late.  This version was not querying until someone dumped
>> the sysfs regs.  In that case, some other idle event could have
>> changed the WKST regs.
>>
>> What you should do is query the WKST regs in your early_resume hook
>> (the same place you query the pending IRQs.)  This way you know
>> exactly when the WKST regs are taken.
>
> However, my 'early_resume' hook is invoked before generating any
> interrupt including PRCM interrupts, because IRQs are disabled by
> arch_suspend_disablel_irqs() in that context.

Ah, yes.  You're right.

> But if I query the WKST regs in the 'resume' hook, I think another
> PRCM interrupts can be generated.

OK, I haven't yet looked closely at your latest version, but reading
the regs directly in the early_resume hook looks OK.

Kevin
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