Re: SYSFS "errors"

Felipe Balbi
2013-02-18T21:57:43Z

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On Mon, Feb 18, 2013 at 04:48:06PM -0500, Alan Stern wrote:
> On Mon, 18 Feb 2013, Felipe Balbi wrote:
>
> > Hi, On Mon, Feb 18, 2013 at 09:49:16AM -0800, Greg KH wrote:
> > > > Input/output error - /sys/devices/cpu/power/autosuspend_delay_ms
> > >
> > > The issue with this file is, if the power.use_autosuspend flag is not
> > > set for the device, then it can't be read or written to. This flag
> > > changes dynamically with the system state
> > > (__pm_runtime_use_autosuspend() can change it), so we can't just not
> > > show the file if the flag is not set properly, sorry.
> > >
> > > So the "error" is correct here, as is the 0644 file value.
> >
> > hmm... we could create the file at pm_runtime_enable() time and remove
> > it on pm_runtime_disable() time, no ? Addin Rafael to Cc
>
> In theory this could be done, although the times would be when runtime
> autosuspend is turned on or off, not when pm_runtime_enable is called.

Right, I got that after replying. Here's a patch I plan to test
tomorrow:

8<------------------------ cut here ----------------------------

From 2cdeeb483383490946cc98727a167843c40d7d27 Mon Sep 17 00:00:00 2001
From: Felipe Balbi <balbi@ti.com>
Date: Mon, 18 Feb 2013 21:20:28 +0200
Subject: [PATCH] base: power: create autosuspend_delay_ms from
pm_runtime_use_autosuspend()

this patch moves the creation of autosuspend_delay_ms
sysfs file to pm_runtime_use_autosuspend() and, conversely,
its deletion to pm_runtime_dont_use_autosuspend.

The idea behind this patch is such that the file in
question is only readable after pm_runtime_use_autosuspend()
has been called for a particular device, so we might
as well move the creation of the file to that place.

Signed-off-by: Felipe Balbi <balbi@ti.com>
---
drivers/base/power/power.h | 4 ++++
drivers/base/power/runtime.c | 6 ++++++
drivers/base/power/sysfs.c | 25 ++++++++++++++++++++++++-
3 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
index b16686a..3822b94 100644
--- a/drivers/base/power/power.h
+++ b/drivers/base/power/power.h
@@ -90,6 +90,8 @@ static inline void device_pm_init(struct device *dev)

extern int dpm_sysfs_add(struct device *dev);
extern void dpm_sysfs_remove(struct device *dev);
+extern int dpm_autosuspend_sysfs_add(struct device *dev);
+extern void dpm_autosuspend_sysfs_remove(struct device *dev);
extern void rpm_sysfs_remove(struct device *dev);
extern int wakeup_sysfs_add(struct device *dev);
extern void wakeup_sysfs_remove(struct device *dev);
@@ -102,6 +104,8 @@ extern void pm_qos_sysfs_remove_flags(struct device *dev);

static inline int dpm_sysfs_add(struct device *dev) { return 0; }
static inline void dpm_sysfs_remove(struct device *dev) {}
+static inline int dpm_autosuspend_sysfs_add(struct device *dev) { return 0; }
+static inline void dpm_autosuspend_sysfs_remove(struct device *dev) {}
static inline void rpm_sysfs_remove(struct device *dev) {}
static inline int wakeup_sysfs_add(struct device *dev) { return 0; }
static inline void wakeup_sysfs_remove(struct device *dev) {}
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 3148b10..a162ba5 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -1266,6 +1266,12 @@ void __pm_runtime_use_autosuspend(struct device *dev, bool use)
old_use = dev->power.use_autosuspend;
dev->power.use_autosuspend = use;
update_autosuspend(dev, old_delay, old_use);
+
+ if (use)
+ dpm_autosuspend_sysfs_add(dev);
+ else
+ dpm_autosuspend_sysfs_remove(dev);
+
spin_unlock_irq(&dev->power.lock);
}
EXPORT_SYMBOL_GPL(__pm_runtime_use_autosuspend);
diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
index 50d16e3..ef2a41c 100644
--- a/drivers/base/power/sysfs.c
+++ b/drivers/base/power/sysfs.c
@@ -609,15 +609,26 @@ static struct attribute *runtime_attrs[] = {
&dev_attr_control.attr,
&dev_attr_runtime_suspended_time.attr,
&dev_attr_runtime_active_time.attr,
- &dev_attr_autosuspend_delay_ms.attr,
#endif /* CONFIG_PM_RUNTIME */
NULL,
};
+
static struct attribute_group pm_runtime_attr_group = {
.name = power_group_name,
.attrs = runtime_attrs,
};

+static struct attribute *runtime_autosuspend_attrs[] = {
+#ifdef CONFIG_PM_RUNTIME
+ &dev_attr_autosuspend_delay_ms.attr,
+#endif /* CONFIG_PM_RUNTIME */
+};
+
+static struct attribute_group pm_runtime_autosuspend_attr_group = {
+ .name = power_group_name,
+ .attrs = runtime_autosuspend_attrs,
+};
+
static struct attribute *pm_qos_latency_attrs[] = {
#ifdef CONFIG_PM_RUNTIME
&dev_attr_pm_qos_resume_latency_us.attr,
@@ -671,6 +682,12 @@ int dpm_sysfs_add(struct device *dev)
return rc;
}

+int dpm_autosuspend_sysfs_add(struct device *dev)
+{
+ return sysfs_merge_group(&dev->kobj,
+ &pm_runtime_autosuspend_attr_group);
+}
+
int wakeup_sysfs_add(struct device *dev)
{
return sysfs_merge_group(&dev->kobj, &pm_wakeup_attr_group);
@@ -712,3 +729,9 @@ void dpm_sysfs_remove(struct device *dev)
sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group);
sysfs_remove_group(&dev->kobj, &pm_attr_group);
}
+
+void dpm_autosuspend_sysfs_remove(struct device *dev)
+{
+ sysfs_unmerge_group(&dev->kobj,
+ &pm_runtime_autosuspend_attr_group);
+}
--
1.8.1.rc1.5.g7e0651a

--
balbi

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