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PM: add kconfig option for deprecated .../power/state files

PATCH New David Brownell 1 participant 1 message Aug 30, 2006

Subsystems (4)
Driver core Suspend to RAM Hibernation Power management core
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David Brownell

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PATCH 1/1 PM: add kconfig option for deprecated .../power/state files

[ resend ... Pavel, ISTR you did ack this but correct me if not ]

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 <[email protected]>
Acked-by Pavel Machek <[email protected]>
kernel/power/Kconfig +11 -0
Index: linux/kernel/power/Kconfig
===================================================================
@@ -53,6 +53,17 @@
 	CAUTION: this option will cause your machine's real-time clock to be
 	set to an invalid time after a resume.
 
+config PM_SYSFS_DEPRECATED
+	bool "Driver model /sys/devices/.../power/state files (DEPRECATED)"
+	depends on PM && SYSFS
+	default n
+	help
+	  The driver model started out with a sysfs file intended to provide
+	  a userspace hook for device power management.  This feature has never
+	  worked very well, except for limited testing purposes, and so it will
+	  be removed.   It's not clear that a generic mechanism could really
+	  handle the wide variability of device power states; any replacements
+	  are likely to be bus or driver specific.
 
 config SOFTWARE_SUSPEND
 	bool "Software Suspend"
drivers/base/power/sysfs.c +6 -0
Index: linux/drivers/base/power/sysfs.c
===================================================================
@@ -7,6 +7,8 @@
 #include "power.h"
 
 
+#ifdef	CONFIG_PM_SYSFS_DEPRECATED
+
 /**
  *	state - Control current power state of device
  *

@@ -67,6 +69,8 @@
 
 static DEVICE_ATTR(state, 0644, state_show, state_store);
 
+#endif	/* CONFIG_PM_SYSFS_DEPRECATED */
+
 /*
  *	wakeup - Report/change current wakeup option for device
  *

@@ -140,7 +144,9 @@
 
 
 static struct attribute * power_attrs[] = {
+#ifdef	CONFIG_PM_SYSFS_DEPRECATED
 	&dev_attr_state.attr,
+#endif
 	&dev_attr_wakeup.attr,
 	NULL,
 };