"Basak, Partha" <[email protected]> writes:
>> From: Kevin Hilman <[email protected]>
>>
>> Currently, we wait until late in the idle path where interrupts are
>> disabled to do runtime-PM-like management for certain special-case
>> devices like GPIO.
>>
>> As a prerequiste to moving GPIO to the new runtime PM framework, move
>> this runtime-PM-like code out of the late idle path into new device
>> idle and resume functions that can be called before interrupts are
>> disabled by CPUidle and/or suspend.
>>
>> In addition, move all the GPIO-specific logic into the GPIO core
>> instead of keeping GPIO-specific knowledge of power-states, context
>> saving etc. in the PM core.
>>
>> Also, call the new device-idle and -resume methods from CPUidle and
>> static suspend path.
>>
>> Signed-off-by: Kevin Hilman <[email protected]>
>> ---
>> arch/arm/mach-omap2/cpuidle34xx.c | 4 ++
>> arch/arm/mach-omap2/pm.h | 2 +
>> arch/arm/mach-omap2/pm24xx.c | 2 +-
>> arch/arm/mach-omap2/pm34xx.c | 38 +++++++++------------
>> arch/arm/plat-omap/gpio.c | 57
>> ++++++++++++++++++++++++--------
>> arch/arm/plat-omap/include/plat/gpio.h | 4 +--
>> 6 files changed, 67 insertions(+), 40 deletions(-)
>>
>> diff --git a/arch/arm/mach-omap2/cpuidle34xx.c
>> b/arch/arm/mach-omap2/cpuidle34xx.c
>> index 0923b82..681d823 100644
>> --- a/arch/arm/mach-omap2/cpuidle34xx.c
>> +++ b/arch/arm/mach-omap2/cpuidle34xx.c
>> @@ -274,9 +274,13 @@ static int omap3_enter_idle_bm(struct
>> cpuidle_device *dev,
>> pwrdm_set_next_pwrst(per_pd, per_next_state);
>>
>> select_state:
>> + omap3_device_idle();
>> +
>> dev->last_state = new_state;
>> ret = omap3_enter_idle(dev, new_state);
>>
>> + omap3_device_resume();
>> +
> In the generic cpu_idle() in process.c, interrupts are already disabled
> before control comes to cpuidle_idle_call() via pm_idle()
> local_irq_disable();
> if (hlt_counter) {
> local_irq_enable();
> cpu_relax();
> } else {
> stop_critical_timings();
> pm_idle();
> start_critical_timings();
> /*
> * This will eventually be removed - pm_idle
> * functions should always return with IRQs
> * enabled.
> */
> WARN_ON(irqs_disabled());
> local_irq_enable();
> }
>
> omap3_enter_idle_bm() will be called from inside cpuidle_idle_call()
> via target_state->enter(dev, target_state).
> So, interrupts are already disabled here.
>
> Am I missing something?
You're right.
I knew this was the case for !CPUIDLE setup, but had thought (without
testing) that the CPUidle core had re-enabled interrupts during the
governor selection process etc.
While I investigate ways to manage this in CPUidle, the following should
be fine for now to include with $SUBJECT patch.
Kevin
diff --git a/arch/arm/mach-omap2/cpuidle34xx.c
b/arch/arm/mach-omap2/cpuidle34xx.c
index 681d823..c5cb9d0 100644
--- a/arch/arm/mach-omap2/cpuidle34xx.c
+++ b/arch/arm/mach-omap2/cpuidle34xx.c
@@ -245,6 +245,14 @@ static int omap3_enter_idle_bm(struct cpuidle_device *dev,
goto select_state;
}
+ /*
+ * Enable IRQs during the device activity checking and idle management.
+ * IRQs are later (re)disabled when entering the actual idle function.
+ * Device idle management that is using runtime PM needs to have
+ * interrupts enabled when calling into the runtime PM core.
+ */
+ local_irq_enable();
+
cx = cpuidle_get_statedata(state);
core_next_state = cx->core_state;
k
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