Messages in this thread | | | Subject | Re: [PATCH v2] PM: runtime: enable wake irq after runtime_suspend hook called | From | Chunfeng Yun <> | Date | Tue, 20 Jul 2021 13:26:58 +0800 |
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On Fri, 2021-07-16 at 14:52 +0200, Rafael J. Wysocki wrote: > On Fri, Jul 16, 2021 at 11:23 AM Chunfeng Yun <chunfeng.yun@mediatek.com> wrote: > > > > When the dedicated wake-irq is level trigger, and it uses the > > consumer's sleep status as the wakeup source, > > This is not a typical case, though, AFAICS. > > So you seem to have a special requirement and you want to change a > generic framework in an incompatible way to accommodate it. > > > that means if the > > consumer is not in sleep state, the wake-irq will be triggered > > when enable it; For this case, need enable the wake-irq after > > invoking the consumer's runtime_suspend() which make the consumer > > enter sleep state. > > > > e.g. > > Assume the wake-irq is a low level trigger type, and the wakeup > > signal comes from the sleep status of consumer. > > The wakeup signal is low level at running time (0), and becomes > > high level when the consumer enters sleep state (runtime_suspend > > (1) is called), a wakeup event at (2) make the consumer exit sleep > > state, then the wakeup signal also becomes low level. > > > > ------------------ > > | ^ ^| > > ---------------- | | -------------- > > |<---(0)--->|<--(1)--| (3) (2) (4) > > > > if enable the wake-irq before calling runtime_suspend during (0), > > an interrupt will arise, it causes resume immediately; > > it works if enable wake-irq ( e.g. at (3) or (4)) after calling > > runtime_suspend. > > > > In this example, can't fix it by using falling edge trigger without > > this patch, the issue will happen as below steps: > > 1. use another wakeup source to wake up the suspended system; > > 2. the consumer's resume() will be called, and exits sleep state; > > 3. the consumer's wakeup signal will fall into low level, due to > > currently the wakeup irq is disabled, the wake-irq is pending; > > 4. the consumer tries to enter runtime suspend, but there is a > > pending wakeup irq, so will resume again, this will repeat > > endlessly. > > > > This patch seems no side effect on edge trigger wake-irq that works > > before. > > > > Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com> > > --- > > v2: add more commit message > > > > I use the falling edge trigger interrupt suggested by Ikjoon [1], it > > works well at firstly when only use this related wakeup source, but > > encounter issues if use other wakeup sources to wakeup platform as > > described in commit message. > > Send out the patch again for further discussion. > > > > [1]: https://patchwork.kernel.org/patch/12190407 > > > > --- > > drivers/base/power/runtime.c | 5 ++--- > > 1 file changed, 2 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c > > index 8a66eaf731e4..90a91b2b1364 100644 > > --- a/drivers/base/power/runtime.c > > +++ b/drivers/base/power/runtime.c > > @@ -639,12 +639,12 @@ static int rpm_suspend(struct device *dev, int rpmflags) > > __update_runtime_status(dev, RPM_SUSPENDING); > > > > callback = RPM_GET_CALLBACK(dev, runtime_suspend); > > - > > - dev_pm_enable_wake_irq_check(dev, true); > > I would suggest adding a wake IRQ flag to indicate that it needs > special handling and modifying the above to take that new flag into > account. > > > retval = rpm_callback(callback, dev); > > if (retval) > > goto fail; > > > > + dev_pm_enable_wake_irq_check(dev, true); > > Then, you can add an entirely new call here, say > dev_pm_enable_wake_irq_complete(dev), that will do the actual enable > for the wake IRQs with the new flag set and nothing for the others. > > > + > > no_callback: > > __update_runtime_status(dev, RPM_SUSPENDED); > > pm_runtime_deactivate_timer(dev); > > @@ -690,7 +690,6 @@ static int rpm_suspend(struct device *dev, int rpmflags) > > return retval; > > > > fail: > > - dev_pm_disable_wake_irq_check(dev); > > And obviously this will really disable wake IRQs with the new flag unset only.
Ok, I'll try it, thanks a lot
> > > __update_runtime_status(dev, RPM_ACTIVE); > > dev->power.deferred_resume = false; > > wake_up_all(&dev->power.wait_queue); > > -- > > 2.18.0 > >
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