Re: [RFC][PATCH 6/8] PM / Sleep: Implement opportunistic sleep

Rafael J. Wysocki
2012-05-03T22:19:51Z

On Friday, May 04, 2012, Arve Hjønnevåg wrote:
> On Thu, May 3, 2012 at 3:20 PM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> > On Thursday, May 03, 2012, Arve Hjønnevåg wrote:
> >> On Thu, May 3, 2012 at 6:28 AM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> >> > On Thursday, May 03, 2012, Arve Hjønnevåg wrote:
> >> >> On Thu, Apr 26, 2012 at 2:52 PM, Rafael J. Wysocki <rjw@sisk.pl> wrote:
> >> >> ...
> >> >> > From: Rafael J. Wysocki <rjw@sisk.pl>
> >> >> > Subject: PM / Sleep: Implement opportunistic sleep, v2
> >> >> >
> >> >> > Introduce a mechanism by which the kernel can trigger global
> >> >> > transitions to a sleep state chosen by user space if there are no
> >> >> > active wakeup sources.
> >> >> >
> >> >> > It consists of a new sysfs attribute, /sys/power/autosleep, that
> >> >> > can be written one of the strings returned by reads from
> >> >> > /sys/power/state, an ordered workqueue and a work item carrying out
> >> >> > the "suspend" operations. If a string representing the system's
> >> >> > sleep state is written to /sys/power/autosleep, the work item
> >> >> > triggering transitions to that state is queued up and it requeues
> >> >> > itself after every execution until user space writes "off" to
> >> >> > /sys/power/autosleep.
> >> >> >
> >> >>
> >> >> This does not work. Writing something other than "off" disabled auto
> >> >> suspend for me.
> >> >
> >> > My bad, sorry about that.
> >> >
> >> >> ...
> >> >> > +static ssize_t autosleep_store(struct kobject *kobj,
> >> >> > + struct kobj_attribute *attr,
> >> >> > + const char *buf, size_t n)
> >> >> > +{
> >> >> > + suspend_state_t state = decode_state(buf, n);
> >> >> > + int error;
> >> >> > +
> >> >> > + if (state == PM_SUSPEND_ON
> >> >> > + && !(strncmp(buf, "off", 3) && strncmp(buf, "off\n", 4)))
> >> >> > + return -EINVAL;
> >> >>
> >> >> Did you mean:
> >> >> if (state == PM_SUSPEND_ON
> >> >> && strcmp(buf, "off") && strcmp(buf, "off\n"))
> >> >> return -EINVAL;
> >> >
> >> >
> >> > Yes, I did.
> >> >
> >> > I'll add the following as an incremental patch on top of the series.
> >> >
> >> > Thanks,
> >> > Rafael
> >> >
> >> > ---
> >> > kernel/power/main.c | 2 +-
> >> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >> >
> >> > Index: linux/kernel/power/main.c
> >> > ===================================================================
> >> > --- linux.orig/kernel/power/main.c
> >> > +++ linux/kernel/power/main.c
> >> > @@ -422,7 +422,7 @@ static ssize_t autosleep_store(struct ko
> >> > int error;
> >> >
> >> > if (state == PM_SUSPEND_ON
> >> > - && !(strncmp(buf, "off", 3) && strncmp(buf, "off\n", 4)))
> >> > + && strncmp(buf, "off", 3) && strncmp(buf, "off\n", 4))
> >> > return -EINVAL;
> >> >
> >> > error = pm_autosleep_set_state(state);
> >>
> >> You still use strncmp here, so anything that starts with "off" is
> >> allowed (and the second strncmp is redundant).
> >
> > Good point. So I'm going to add the patch below after all.
> > OK to add your sign-off to it?
> >
>
> Yes.

OK, done.