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Date: Wed, 13 May 2015 01:48:36 +0200
From: "Rafael J. Wysocki" <rjw@...ysocki.net>
To: Alexandra Yates <alexandra.yates@...ux.intel.com>
Cc: linux-pm@...r.kernel.org, Peter Zijlstra <peterz@...radead.org>,
Thomas Gleixner <tglx@...utronix.de>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] Report interrupt(s) that caused system wakeup
On Tuesday, May 12, 2015 11:18:59 AM Alexandra Yates wrote:
> Add a new IRQ flag named IRQD_WAKEUP_TRIGGERED. This flag is set when a
> given IRQ fires after it has been armed for system wakeup. The flag is
> cleared before arming the IRQ for system wakeup during the next system
> suspend. This feature makes possible to check which IRQs might have
> woken the system up from sleep last time it was suspended.
>
> Add a new sysfs attribute under /sys/power/ named: pm_last_wakeup_irqs
> when read, will return a list of IRQs with the new flag set. That will
> be useful for system wakeup diagnostics.
>
> Signed-off-by: Alexandra Yates <alexandra.yates@...ux.intel.com>
> ---
> Documentation/ABI/testing/sysfs-power | 11 +++++++++++
> drivers/base/power/wakeup.c | 25 +++++++++++++++++++++++++
> include/linux/irq.h | 7 +++++++
> include/linux/suspend.h | 1 +
> kernel/irq/pm.c | 2 ++
> kernel/power/main.c | 23 +++++++++++++++++++++++
> 6 files changed, 69 insertions(+)
>
> diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power
> index f455181..a28b155 100644
> --- a/Documentation/ABI/testing/sysfs-power
> +++ b/Documentation/ABI/testing/sysfs-power
> @@ -256,3 +256,14 @@ Description:
> Writing a "1" enables this printing while writing a "0"
> disables it. The default value is "0". Reading from this file
> will display the current value.
> +
> +What: /sys/power/pm_last_wakeup_irqs
> +Date: April 2015
> +Contact: Alexandra Yates <alexandra.yates@...ux.intel.org>
> +Description:
> + The /sys/power/pm_last_wakeup_irqs file allows user space
> + to identify and report the IRQs responsible from waking the
> + system up from sleep. The IRQD_WAKEUP_TRIGGERED flag is set and
> + reported when the given IRQ fires after it has been armed for
> + system wakeup. This output is useful for system wakeup
> + diagnostics.
> diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
> index 7b5ad9a..fa84509 100644
> --- a/drivers/base/power/wakeup.c
> +++ b/drivers/base/power/wakeup.c
> @@ -755,6 +755,31 @@ void pm_wakeup_clear(void)
> pm_abort_suspend = false;
> }
>
> +/*
> + * pm_get_last_wakeup_irqs - Parses interrupts to identify which one
> + * caused the system to wake up from suspend-to-idle.
> + * @buf: keeps track of the irqs that casued the system to wakeup
> + */
> +ssize_t pm_get_last_wakeup_irqs(char *buf, size_t size)
> +{
> + struct irq_desc *desc;
> + int irq;
> + char *str = buf;
> + char *end = buf + size;
> +
> + if (pm_abort_suspend) {
> + for_each_irq_desc(irq, desc)
> + if (irqd_triggered_wakeup(&desc->irq_data))
> + str += scnprintf(str, end - str, "%d ", irq);
> +
> + if (str != buf)
> + str--;
> +
> + return (str - buf);
> + }
> + return 0;
> +}
Since you put the only caller of this under CONFIG_PM_SLEEP_DEBUG, it should
depend on that option too I suppose?.
> +
> /**
> * pm_get_wakeup_count - Read the number of registered wakeup events.
> * @count: Address to store the value at.
> diff --git a/include/linux/irq.h b/include/linux/irq.h
> index 62c6901..9b1a31f 100644
> --- a/include/linux/irq.h
> +++ b/include/linux/irq.h
> @@ -182,6 +182,7 @@ struct irq_data {
> * IRQD_IRQ_MASKED - Masked state of the interrupt
> * IRQD_IRQ_INPROGRESS - In progress state of the interrupt
> * IRQD_WAKEUP_ARMED - Wakeup mode armed
> + * IRQD_WAKEUP_TRIGGERED - Triggered system wakeup
> */
> enum {
> IRQD_TRIGGER_MASK = 0xf,
> @@ -196,8 +197,14 @@ enum {
> IRQD_IRQ_MASKED = (1 << 17),
> IRQD_IRQ_INPROGRESS = (1 << 18),
> IRQD_WAKEUP_ARMED = (1 << 19),
> + IRQD_WAKEUP_TRIGGERED = (1 << 20),
> };
>
> +static inline bool irqd_triggered_wakeup(struct irq_data *d)
> +{
> + return d->state_use_accessors & IRQD_WAKEUP_TRIGGERED;
> +}
> +
> static inline bool irqd_is_setaffinity_pending(struct irq_data *d)
> {
> return d->state_use_accessors & IRQD_SETAFFINITY_PENDING;
> diff --git a/include/linux/suspend.h b/include/linux/suspend.h
> index 5efe743..7cadded 100644
> --- a/include/linux/suspend.h
> +++ b/include/linux/suspend.h
> @@ -378,6 +378,7 @@ void restore_processor_state(void);
> /* kernel/power/main.c */
> extern int register_pm_notifier(struct notifier_block *nb);
> extern int unregister_pm_notifier(struct notifier_block *nb);
> +extern ssize_t pm_get_last_wakeup_irqs(char *buf, size_t size);
And it would be good to put this header under CONFIG_PM_SLEEP_DEBUG too for
completeness.
>
> #define pm_notifier(fn, pri) { \
> static struct notifier_block fn##_nb = \
> diff --git a/kernel/irq/pm.c b/kernel/irq/pm.c
> index 5204a6d..52dc34c 100644
> --- a/kernel/irq/pm.c
> +++ b/kernel/irq/pm.c
> @@ -22,6 +22,7 @@ bool irq_pm_check_wakeup(struct irq_desc *desc)
> desc->depth++;
> irq_disable(desc);
> pm_system_wakeup();
> + irqd_set(&desc->irq_data, IRQD_WAKEUP_TRIGGERED);
> return true;
> }
> return false;
> @@ -73,6 +74,7 @@ static bool suspend_device_irq(struct irq_desc *desc, int irq)
> if (!desc->action || desc->no_suspend_depth)
> return false;
>
> + irqd_clear(&desc->irq_data, IRQD_WAKEUP_TRIGGERED);
> if (irqd_is_wakeup_set(&desc->irq_data)) {
> irqd_set(&desc->irq_data, IRQD_WAKEUP_ARMED);
> /*
> diff --git a/kernel/power/main.c b/kernel/power/main.c
> index 86e8157..8215ca0d 100644
> --- a/kernel/power/main.c
> +++ b/kernel/power/main.c
> @@ -272,6 +272,28 @@ static inline void pm_print_times_init(void)
> {
> pm_print_times_enabled = !!initcall_debug;
> }
> +
> +static ssize_t pm_last_wakeup_irqs_show(struct kobject *kobj,
> + struct kobj_attribute *attr,
> + char *buf)
> +{
> + size_t ret;
> +
> + ret = pm_get_last_wakeup_irqs(buf, PAGE_SIZE);
> + if (ret)
> + buf[ret++] = '\n';
> +
> + return ret;
> +}
> +
> +static ssize_t pm_last_wakeup_irqs_store(struct kobject *kobj,
> + struct kobj_attribute *attr,
> + const char *buf, size_t n)
> +{
> + return -EINVAL;
> +}
> +power_attr(pm_last_wakeup_irqs);
> +
> #else /* !CONFIG_PP_SLEEP_DEBUG */
> static inline void pm_print_times_init(void) {}
> #endif /* CONFIG_PM_SLEEP_DEBUG */
> @@ -592,6 +614,7 @@ static struct attribute * g[] = {
> #ifdef CONFIG_PM_SLEEP
> &pm_async_attr.attr,
> &wakeup_count_attr.attr,
> + &pm_last_wakeup_irqs_attr.attr,
That needs to depend on CONFIG_PM_SLEEP_DEBUG. Maybe put it next to the
pm_print_times_attr.attr?
> #ifdef CONFIG_PM_AUTOSLEEP
> &autosleep_attr.attr,
> #endif
>
Please CC Thomas and Peter (CCed now) for the IRQ core changes when sending the
next version.
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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