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

Rafael J. Wysocki
2012-05-03T22:15:37Z

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?

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)))
+ && strcmp(buf, "off") && strcmp(buf, "off\n"))
return -EINVAL;

error = pm_autosleep_set_state(state);