Re: Runtime device power management in userspace

[Pavel Machek <pavel@ucw.cz>]

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On Po 26-12-05 17:47:23, Alan Stern wrote:
> On Mon, 26 Dec 2005, Patrick Mochel wrote:

> > To that effect, the per-device power file and its semantics should go away
> > completely and replaced with something that supports this new API.
> 
> Allow me to direct your attention to this posting:
> 
> http://lists.osdl.org/pipermail/linux-pm/2005-September/001421.html
> 
> and the follow-on messages.  They implement exactly the type of API you're 
> talking about.  When I have some time available I will rework the patches, 
> with improvements as suggested by the discussions on the mailing list, and 
> submit them.

Ok, what about this as a first step? It unbreaks the interface between
kernel and user, and allows something like patches above to be taken
in future, without userland changes.
								Pavel

diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
--- a/drivers/base/power/sysfs.c
+++ b/drivers/base/power/sysfs.c
@@ -33,15 +33,12 @@ static ssize_t state_show(struct device 
 static ssize_t state_store(struct device * dev, struct device_attribute *attr, const char * buf, size_t n)
 {
 	pm_message_t state;
-	char * rest;
-	int error = 0;
+	int error = -EINVAL;
 
-	state.event = simple_strtoul(buf, &rest, 10);
-	if (*rest)
-		return -EINVAL;
-	if (state.event)
+	state.event = PM_EVENT_SUSPEND;
+	if ((n == 2) && !strncmp(buf, "on", min(n, 2)))
 		error = dpm_runtime_suspend(dev, state);
-	else
+	if ((n == 7) && !strncmp(buf, "suspend", min(n, 7)))
 		dpm_runtime_resume(dev);
 	return error ? error : n;
 }


-- 
Thanks, Sharp!

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