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Message-ID: <4822176.o10EEduFBa@aspire.rjw.lan>
Date: Thu, 08 Dec 2016 01:10:59 +0100
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Tony Lindgren <tony@...mide.com>
Cc: "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
Alan Stern <stern@...land.harvard.edu>,
Brian Norris <briannorris@...omium.org>,
Dmitry Torokhov <dmitry.torokhov@...il.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Grygorii Strashko <grygorii.strashko@...com>,
Len Brown <len.brown@...el.com>, Nishanth Menon <nm@...com>,
Pavel Machek <pavel@....cz>,
Ulf Hansson <ulf.hansson@...aro.org>, linux-pm@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-omap@...r.kernel.org
Subject: Re: [PATCH] PM / wakeirq: Fix dedicated wakeirq for drivers not using autosuspend
On Monday, December 05, 2016 04:38:16 PM Tony Lindgren wrote:
> I noticed some wakeirq flakeyness with consumer drivers not using
> autosuspend. For drivers not using autosuspend, the wakeirq may never
> get unmasked in rpm_suspend() because of irq desc->depth.
>
> We are configuring dedicated wakeirqs to start with IRQ_NOAUTOEN as we
> naturally don't want them running until rpm_suspend() is called.
>
> However, when a consumer driver initially calls pm_runtime_get, we now
> wrongly start with disable_irq_nosync() call on the dedicated wakeirq
> that is disabled to start with.
>
> This causes desc->depth to toggle between 1 and 2 instead of the usual
> 0 and 1. This can prevent enable_irq() from unmasking the wakeirq as
> that only happens at desc->depth 1.
>
> This does not necessarily show up with drivers using autosuspend as
> there is time for disable_irq_nosync() before rpm_suspend() gets called
> after the autosuspend timeout.
>
> Let's fix the issue by adding wirq->status that lazily gets set on
> the first rpm_suspend(). We also need PM runtime core private functions
> for dev_pm_enable_wake_irq_check() and dev_pm_disable_wake_irq_check()
> so we can enable the dedicated wakeirq on the first rpm_suspend().
>
> While at it, let's also fix the comments for dev_pm_enable_wake_irq()
> and dev_pm_disable_wake_irq(). Those can still be used by the consumer
> drivers as needed because the irq core manages the interrupt usecount
> for us.
>
> Fixes: 4990d4fe327b ("PM / Wakeirq: Add automated device wake IRQ
> handling")
> Signed-off-by: Tony Lindgren <tony@...mide.com>
> ---
> drivers/base/power/power.h | 19 ++++++++++-
> drivers/base/power/runtime.c | 8 ++---
> drivers/base/power/wakeirq.c | 76 ++++++++++++++++++++++++++++++++++++++------
> 3 files changed, 88 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
> --- a/drivers/base/power/power.h
> +++ b/drivers/base/power/power.h
> @@ -21,14 +21,22 @@ extern void pm_runtime_init(struct device *dev);
> extern void pm_runtime_reinit(struct device *dev);
> extern void pm_runtime_remove(struct device *dev);
>
> +#define WAKE_IRQ_DEDICATED_ALLOCATED BIT(0)
> +#define WAKE_IRQ_DEDICATED_MANAGED BIT(1)
> +#define WAKE_IRQ_DEDICATED_MASK (WAKE_IRQ_DEDICATED_ALLOCATED | \
> + WAKE_IRQ_DEDICATED_MANAGED)
> +
> struct wake_irq {
> struct device *dev;
> + unsigned int status;
> int irq;
> - bool dedicated_irq:1;
> };
>
> extern void dev_pm_arm_wake_irq(struct wake_irq *wirq);
> extern void dev_pm_disarm_wake_irq(struct wake_irq *wirq);
> +extern void dev_pm_enable_wake_irq_check(struct device *dev,
> + bool can_change_status);
> +extern void dev_pm_disable_wake_irq_check(struct device *dev);
>
> #ifdef CONFIG_PM_SLEEP
>
> @@ -104,6 +112,15 @@ static inline void dev_pm_disarm_wake_irq(struct wake_irq *wirq)
> {
> }
>
> +static inline void dev_pm_enable_wake_irq_check(struct device *dev,
> + bool can_change_status)
> +{
> +}
> +
> +static inline void dev_pm_disable_wake_irq_check(struct device *dev)
> +{
> +}
> +
> #endif
>
> #ifdef CONFIG_PM_SLEEP
> diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
> --- a/drivers/base/power/runtime.c
> +++ b/drivers/base/power/runtime.c
> @@ -592,7 +592,7 @@ static int rpm_suspend(struct device *dev, int rpmflags)
>
> callback = RPM_GET_CALLBACK(dev, runtime_suspend);
>
> - dev_pm_enable_wake_irq(dev);
> + dev_pm_enable_wake_irq_check(dev, true);
> retval = rpm_callback(callback, dev);
> if (retval)
> goto fail;
> @@ -631,7 +631,7 @@ static int rpm_suspend(struct device *dev, int rpmflags)
> return retval;
>
> fail:
> - dev_pm_disable_wake_irq(dev);
> + dev_pm_disable_wake_irq_check(dev);
> __update_runtime_status(dev, RPM_ACTIVE);
> dev->power.deferred_resume = false;
> wake_up_all(&dev->power.wait_queue);
> @@ -814,12 +814,12 @@ static int rpm_resume(struct device *dev, int rpmflags)
>
> callback = RPM_GET_CALLBACK(dev, runtime_resume);
>
> - dev_pm_disable_wake_irq(dev);
> + dev_pm_disable_wake_irq_check(dev);
> retval = rpm_callback(callback, dev);
> if (retval) {
> __update_runtime_status(dev, RPM_SUSPENDED);
> pm_runtime_cancel_pending(dev);
> - dev_pm_enable_wake_irq(dev);
> + dev_pm_enable_wake_irq_check(dev, false);
> } else {
> no_callback:
> __update_runtime_status(dev, RPM_ACTIVE);
> diff --git a/drivers/base/power/wakeirq.c b/drivers/base/power/wakeirq.c
> --- a/drivers/base/power/wakeirq.c
> +++ b/drivers/base/power/wakeirq.c
> @@ -110,8 +110,10 @@ void dev_pm_clear_wake_irq(struct device *dev)
> dev->power.wakeirq = NULL;
> spin_unlock_irqrestore(&dev->power.lock, flags);
>
> - if (wirq->dedicated_irq)
> + if (wirq->status & WAKE_IRQ_DEDICATED_ALLOCATED) {
> free_irq(wirq->irq, wirq);
> + wirq->status &= ~WAKE_IRQ_DEDICATED_MASK;
> + }
> kfree(wirq);
> }
> EXPORT_SYMBOL_GPL(dev_pm_clear_wake_irq);
> @@ -181,7 +183,6 @@ int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq)
>
> wirq->dev = dev;
> wirq->irq = irq;
> - wirq->dedicated_irq = true;
> irq_set_status_flags(irq, IRQ_NOAUTOEN);
>
> /*
> @@ -197,6 +198,8 @@ int dev_pm_set_dedicated_wake_irq(struct device *dev, int irq)
> if (err)
> goto err_free_irq;
>
> + wirq->status = WAKE_IRQ_DEDICATED_ALLOCATED;
> +
> return err;
>
> err_free_irq:
> @@ -212,9 +215,9 @@ EXPORT_SYMBOL_GPL(dev_pm_set_dedicated_wake_irq);
> * dev_pm_enable_wake_irq - Enable device wake-up interrupt
> * @dev: Device
> *
> - * Called from the bus code or the device driver for
> - * runtime_suspend() to enable the wake-up interrupt while
> - * the device is running.
> + * Optionally called from the bus code or the device driver for
> + * runtime_resume() to override the PM runtime core managed wake-up
> + * interrupt handling to enable the wake-up interrupt.
> *
> * Note that for runtime_suspend()) the wake-up interrupts
> * should be unconditionally enabled unlike for suspend()
> @@ -224,7 +227,7 @@ void dev_pm_enable_wake_irq(struct device *dev)
> {
> struct wake_irq *wirq = dev->power.wakeirq;
>
> - if (wirq && wirq->dedicated_irq)
> + if (wirq && (wirq->status & WAKE_IRQ_DEDICATED_ALLOCATED))
> enable_irq(wirq->irq);
> }
> EXPORT_SYMBOL_GPL(dev_pm_enable_wake_irq);
> @@ -233,20 +236,73 @@ EXPORT_SYMBOL_GPL(dev_pm_enable_wake_irq);
> * dev_pm_disable_wake_irq - Disable device wake-up interrupt
> * @dev: Device
> *
> - * Called from the bus code or the device driver for
> - * runtime_resume() to disable the wake-up interrupt while
> - * the device is running.
> + * Optionally called from the bus code or the device driver for
> + * runtime_suspend() to override the PM runtime core managed wake-up
> + * interrupt handling to disable the wake-up interrupt.
> */
> void dev_pm_disable_wake_irq(struct device *dev)
> {
> struct wake_irq *wirq = dev->power.wakeirq;
>
> - if (wirq && wirq->dedicated_irq)
> + if (wirq && (wirq->status & WAKE_IRQ_DEDICATED_ALLOCATED))
> disable_irq_nosync(wirq->irq);
> }
> EXPORT_SYMBOL_GPL(dev_pm_disable_wake_irq);
>
> /**
> + * dev_pm_enable_wake_irq_check - Checks and enables wake-up interrupt
> + * @dev: Device
> + * @can_change_status: Can change wake-up interrupt status
> + *
> + * Enables wakeirq conditionally. We need to enable wake-up interrupt
> + * lazily on the first rpm_suspend(). This is needed as the consumer device
> + * starts in RPM_SUSPENDED state, and the the first pm_runtime_get() would
> + * otherwise try to disable already disabled wakeirq. The wake-up interrupt
> + * starts disabled with IRQ_NOAUTOEN set.
> + *
> + * Should be only called from rpm_suspend() and rpm_resume() path.
> + * Caller must hold &dev->power.lock to change wirq->status
> + */
> +void dev_pm_enable_wake_irq_check(struct device *dev,
> + bool can_change_status)
> +{
> + struct wake_irq *wirq = dev->power.wakeirq;
> +
> + if (!wirq || !((wirq->status & WAKE_IRQ_DEDICATED_MASK)))
> + return;
> +
> + if (likely(wirq->status & WAKE_IRQ_DEDICATED_MANAGED)) {
> + goto enable;
> + } else if (can_change_status) {
> + wirq->status |= WAKE_IRQ_DEDICATED_MANAGED;
> + goto enable;
> + }
> +
> + return;
> +
> +enable:
> + enable_irq(wirq->irq);
> +}
> +
> +/**
> + * dev_pm_disable_wake_irq_check - Checks and disables wake-up interrupt
> + * @dev: Device
> + *
> + * Disables wake-up interrupt conditionally based on status.
> + * Should be only called from rpm_suspend() and rpm_resume() path.
> + */
> +void dev_pm_disable_wake_irq_check(struct device *dev)
> +{
> + struct wake_irq *wirq = dev->power.wakeirq;
> +
> + if (!wirq || !((wirq->status & WAKE_IRQ_DEDICATED_MASK)))
> + return;
> +
> + if (wirq->status & WAKE_IRQ_DEDICATED_MANAGED)
> + disable_irq_nosync(wirq->irq);
> +}
> +
> +/**
> * dev_pm_arm_wake_irq - Arm device wake-up
> * @wirq: Device wake-up interrupt
> *
>
Applied.
Thanks,
Rafael
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