On Friday, July 20, 2012, Todd Poynor wrote:
> Signed-off-by: Todd Poynor <toddpoy...@google.com>
Applied to the linux-next branch of the linux-pm.git tree, as v3.7 material.
Thanks,
Rafael
> ---
> drivers/base/power/wakeup.c | 29 +++++++++++++++++++++++++++++
> 1 files changed, 29 insertions(+), 0 deletions(-)
>
> A driver or app may repeatedly request a wakeup source while the system
> is attempting to enter suspend, which may indicate a bug or at least
> point out a highly active system component that is responsible for
> decreased battery life on a mobile device. Even when the incidence
> of suspend abort is not severe, identifying wakeup sources that
> frequently abort suspend can be a useful clue for power management
> analysis.
>
> In some cases the existing stats can point out the offender where there is
> an unexpectedly high activation count that stands out from the others, but
> in other cases the wakeup source frequently taken just after the rest of
> the system thinks its time to suspend might not stand out in the overall
> stats.
>
> It is also often useful to have information about what's been happening
> recently, rather than totals of all activity for the system boot.
>
> It's suggested to dump a line about which wakeup source
> aborted suspend to aid analysis of these situations.
>
> v2
> use ktime_to_ns() instead of comparisons on .tv64 field
>
> diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
> index cbb463b..8a0a9ca 100644
> --- a/drivers/base/power/wakeup.c
> +++ b/drivers/base/power/wakeup.c
> @@ -649,6 +649,31 @@ void pm_wakeup_event(struct device *dev, unsigned int
> msec)
> }
> EXPORT_SYMBOL_GPL(pm_wakeup_event);
>
> +static void print_active_wakeup_sources(void)
> +{
> + struct wakeup_source *ws;
> + int active = 0;
> + struct wakeup_source *last_activity_ws = NULL;
> +
> + rcu_read_lock();
> + list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
> + if (ws->active) {
> + pr_info("active wakeup source: %s\n", ws->name);
> + active = 1;
> + } else if (!active &&
> + (!last_activity_ws ||
> + ktime_to_ns(ws->last_time) >
> + ktime_to_ns(last_activity_ws->last_time))) {
> + last_activity_ws = ws;
> + }
> + }
> +
> + if (!active && last_activity_ws)
> + pr_info("last active wakeup source: %s\n",
> + last_activity_ws->name);
> + rcu_read_unlock();
> +}
> +
> /**
> * pm_wakeup_pending - Check if power transition in progress should be
> aborted.
> *
> @@ -671,6 +696,10 @@ bool pm_wakeup_pending(void)
> events_check_enabled = !ret;
> }
> spin_unlock_irqrestore(&events_lock, flags);
> +
> + if (ret)
> + print_active_wakeup_sources();
> +
> return ret;
> }
>
>
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