From 047bda36150d11422b2c7bacca1df324c909c0b3 Mon Sep 17 00:00:00 2001
From: David Brownell <david-b@pacbell.net>
Date: Wed, 30 Aug 2006 14:12:48 -0700
Subject: PM: update docs for writing .../power/state

Updates to match current code:

 - Make writes to the /sys/devices/.../power/state files fail cleanly
   if the device requires the irqs-off call variants.

 - Fix comments describing the /sys/devices/.../power/state file writes
   to match the code; the last several releases have invalidated the
   previous text.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 drivers/base/power/sysfs.c | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

(limited to 'drivers/base/power/sysfs.c')

diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
index 40d7242a07c..e55b3c2779e 100644
--- a/drivers/base/power/sysfs.c
+++ b/drivers/base/power/sysfs.c
@@ -11,18 +11,23 @@
  *	state - Control current power state of device
  *
  *	show() returns the current power state of the device. '0' indicates
- *	the device is on. Other values (1-3) indicate the device is in a low
+ *	the device is on. Other values (2) indicate the device is in some low
  *	power state.
  *
- *	store() sets the current power state, which is an integer value
- *	between 0-3. If the device is on ('0'), and the value written is
- *	greater than 0, then the device is placed directly into the low-power
- *	state (via its driver's ->suspend() method).
- *	If the device is currently in a low-power state, and the value is 0,
- *	the device is powered back on (via the ->resume() method).
- *	If the device is in a low-power state, and a different low-power state
- *	is requested, the device is first resumed, then suspended into the new
- *	low-power state.
+ *	store() sets the current power state, which is an integer valued
+ *	0, 2, or 3.  Devices with bus.suspend_late(), or bus.resume_early()
+ *	methods fail this operation; those methods couldn't be called.
+ *	Otherwise,
+ *
+ *	- If the recorded dev->power.power_state.event matches the
+ *	  target value, nothing is done.
+ *	- If the recorded event code is nonzero, the device is reactivated
+ *	  by calling bus.resume() and/or class.resume().
+ *	- If the target value is nonzero, the device is suspended by
+ *	  calling class.suspend() and/or bus.suspend() with event code
+ *	  PM_EVENT_SUSPEND.
+ *
+ *	This mechanism is DEPRECATED and should only be used for testing.
  */
 
 static ssize_t state_show(struct device * dev, struct device_attribute *attr, char * buf)
@@ -38,6 +43,10 @@ static ssize_t state_store(struct device * dev, struct device_attribute *attr, c
 	pm_message_t state;
 	int error = -EINVAL;
 
+	/* disallow incomplete suspend sequences */
+	if (dev->bus && (dev->bus->suspend_late || dev->bus->resume_early))
+		return error;
+
 	state.event = PM_EVENT_SUSPEND;
 	/* Older apps expected to write "3" here - confused with PCI D3 */
 	if ((n == 1) && !strcmp(buf, "3"))
-- 
cgit v1.2.3


From 2bca293e56b6a8cd16bb6e70a09b2adac9c723b5 Mon Sep 17 00:00:00 2001
From: David Brownell <david-b@pacbell.net>
Date: Wed, 30 Aug 2006 13:54:36 -0700
Subject: PM: add kconfig option for deprecated .../power/state files

Add a new PM_SYSFS_DEPRECATED config option to control whether or
not the /sys/devices/.../power/state files are provided.  This will
make it easier to get rid of that mechanism when the time comes,
and to verify that userspace tools work right without it.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
 drivers/base/power/sysfs.c | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'drivers/base/power/sysfs.c')

diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
index e55b3c2779e..2d47517dbe3 100644
--- a/drivers/base/power/sysfs.c
+++ b/drivers/base/power/sysfs.c
@@ -7,6 +7,8 @@
 #include "power.h"
 
 
+#ifdef	CONFIG_PM_SYSFS_DEPRECATED
+
 /**
  *	state - Control current power state of device
  *
@@ -66,6 +68,8 @@ static ssize_t state_store(struct device * dev, struct device_attribute *attr, c
 static DEVICE_ATTR(state, 0644, state_show, state_store);
 
 
+#endif	/* CONFIG_PM_SYSFS_DEPRECATED */
+
 /*
  *	wakeup - Report/change current wakeup option for device
  *
@@ -139,7 +143,9 @@ static DEVICE_ATTR(wakeup, 0644, wake_show, wake_store);
 
 
 static struct attribute * power_attrs[] = {
+#ifdef	CONFIG_PM_SYSFS_DEPRECATED
 	&dev_attr_state.attr,
+#endif
 	&dev_attr_wakeup.attr,
 	NULL,
 };
-- 
cgit v1.2.3