Merge bk://linux.bkbits.net/linux-2.5

into kernel.bkbits.net:/home/mochel/linux-2.5-power

arch/i386/Makefile

@@ -96,6 +96,7 @@ drivers-$(CONFIG_MATH_EMULATION)	+= arch/i386/math-emu/
 drivers-$(CONFIG_PCI)			+= arch/i386/pci/
 # must be linked after kernel/
 drivers-$(CONFIG_OPROFILE)		+= arch/i386/oprofile/
+drivers-$(CONFIG_PM)			+= arch/i386/power/
 
 CFLAGS += $(mflags-y)
 AFLAGS += $(mflags-y)

arch/i386/kernel/Makefile

@@ -17,9 +17,7 @@ obj-$(CONFIG_MCA)		+= mca.o
 obj-$(CONFIG_X86_MSR)		+= msr.o
 obj-$(CONFIG_X86_CPUID)		+= cpuid.o
 obj-$(CONFIG_MICROCODE)		+= microcode.o
-obj-$(CONFIG_PM)		+= suspend.o
 obj-$(CONFIG_APM)		+= apm.o
-obj-$(CONFIG_SOFTWARE_SUSPEND)	+= suspend_asm.o
 obj-$(CONFIG_X86_SMP)		+= smp.o smpboot.o
 obj-$(CONFIG_X86_TRAMPOLINE)	+= trampoline.o
 obj-$(CONFIG_X86_MPPARSE)	+= mpparse.o

arch/i386/power/Makefile

+obj-$(CONFIG_PM)		+= cpu.o
+obj-$(CONFIG_SOFTWARE_SUSPEND)	+= swsusp.o

arch/i386/kernel/suspend_asm.S → arch/i386/power/swsusp.S

@@ -8,11 +8,10 @@
 
 	.text
 
-ENTRY(do_magic)
+ENTRY(swsusp_arch_suspend)
 	pushl %ebx
 	cmpl $0,8(%esp)
 	jne .L1450
-	call do_magic_suspend_1
 	call save_processor_state
 
 	movl %esp, saved_context_esp
@@ -25,14 +24,13 @@ ENTRY(do_magic)
 	movl %edi, saved_context_edi
 	pushfl ; popl saved_context_eflags
 
-	call do_magic_suspend_2
+	call swsusp_suspend
 	jmp .L1449
 	.p2align 4,,7
 .L1450:
 	movl $swapper_pg_dir-__PAGE_OFFSET,%ecx
 	movl %ecx,%cr3
 
-	call do_magic_resume_1
 	movl $0,loop
 	cmpl $0,nr_copy_pages
 	je .L1453
@@ -80,7 +78,7 @@ ENTRY(do_magic)
 	movl saved_context_edi, %edi
 	call restore_processor_state
 	pushl saved_context_eflags ; popfl
-	call do_magic_resume_2
+	call swsusp_resume
 .L1449:
 	popl %ebx
 	ret
@@ -91,4 +89,4 @@ loop:
 loop2:
        .quad 0
        .previous
-	
\ No newline at end of file
+

drivers/acpi/sleep/main.c

@@ -41,7 +41,6 @@ static u32 acpi_suspend_states[] = {
 
 static int acpi_pm_prepare(u32 state)
 {
-	int error = 0;
 	u32 acpi_state = acpi_suspend_states[state];
 
 	if (!sleep_states[acpi_state])
@@ -56,21 +55,9 @@ static int acpi_pm_prepare(u32 state)
 		acpi_set_firmware_waking_vector(
 			(acpi_physical_address) acpi_wakeup_address);
 	}
-
 	ACPI_FLUSH_CPU_CACHE();
-
-	/* Do arch specific saving of state. */
-	if (state > PM_SUSPEND_STANDBY) {
-		if ((error = acpi_save_state_mem()))
-			goto Err;
-	}
-
 	acpi_enter_sleep_state_prep(acpi_state);
-
 	return 0;
- Err:
-	acpi_set_firmware_waking_vector(0);
-	return error;
 }
 
 
@@ -90,6 +77,15 @@ static int acpi_pm_enter(u32 state)
 	u32 acpi_state = acpi_suspend_states[state];
 
 	ACPI_FLUSH_CPU_CACHE();
+
+	/* Do arch specific saving of state. */
+	if (state > PM_SUSPEND_STANDBY) {
+		int error = acpi_save_state_mem();
+		if (error)
+			return error;
+	}
+
+
 	local_irq_save(flags);
 	switch (state)
 	{
@@ -114,6 +110,15 @@ static int acpi_pm_enter(u32 state)
 	local_irq_restore(flags);
 	printk(KERN_DEBUG "Back to C!\n");
 
+	/* restore processor state
+	 * We should only be here if we're coming back from STR or STD.
+	 * And, in the case of the latter, the memory image should have already
+	 * been loaded from disk.
+	 */
+	if (state > PM_SUSPEND_STANDBY)
+		acpi_restore_state_mem();
+
+
 	return ACPI_SUCCESS(status) ? 0 : -EFAULT;
 }
 
@@ -130,14 +135,6 @@ static int acpi_pm_finish(u32 state)
 {
 	acpi_leave_sleep_state(state);
 
-	/* restore processor state
-	 * We should only be here if we're coming back from STR or STD.
-	 * And, in the case of the latter, the memory image should have already
-	 * been loaded from disk.
-	 */
-	if (state > ACPI_STATE_S1)
-		acpi_restore_state_mem();
-
 	/* reset firmware waking vector */
 	acpi_set_firmware_waking_vector((acpi_physical_address) 0);
 
@@ -149,6 +146,20 @@ static int acpi_pm_finish(u32 state)
 }
 
 
+int acpi_suspend(u32 acpi_state)
+{
+	u32 states[] = {
+		[1]	= PM_SUSPEND_STANDBY,
+		[3]	= PM_SUSPEND_MEM,
+		[4]	= PM_SUSPEND_DISK,
+	};
+
+	if (acpi_state <= 4 && states[acpi_state])
+		return pm_suspend(states[acpi_state]);
+	return -EINVAL;
+}
+
+
 static struct pm_ops acpi_pm_ops = {
 	.prepare	= acpi_pm_prepare,
 	.enter		= acpi_pm_enter,

drivers/acpi/sleep/proc.c

@@ -13,12 +13,71 @@
 
 #include "sleep.h"
 
+#define ACPI_SYSTEM_FILE_SLEEP		"sleep"
 #define ACPI_SYSTEM_FILE_ALARM		"alarm"
 
 #define _COMPONENT		ACPI_SYSTEM_COMPONENT
 ACPI_MODULE_NAME		("sleep")
 
 
+static int acpi_system_sleep_seq_show(struct seq_file *seq, void *offset)
+{
+	int			i;
+
+	ACPI_FUNCTION_TRACE("acpi_system_sleep_seq_show");
+
+	for (i = 0; i <= ACPI_STATE_S5; i++) {
+		if (sleep_states[i]) {
+			seq_printf(seq,"S%d ", i);
+			if (i == ACPI_STATE_S4 && acpi_gbl_FACS->S4bios_f)
+				seq_printf(seq, "S4bios ");
+		}
+	}
+
+	seq_puts(seq, "\n");
+
+	return 0;
+}
+
+static int acpi_system_sleep_open_fs(struct inode *inode, struct file *file)
+{
+	return single_open(file, acpi_system_sleep_seq_show, PDE(inode)->data);
+}
+
+static int
+acpi_system_write_sleep (
+	struct file		*file,
+	const char		*buffer,
+	size_t			count,
+	loff_t			*ppos)
+{
+	char	str[12];
+	u32	state = 0;
+	int	error = 0;
+
+	if (count > sizeof(str) - 1)
+		goto Done;
+	memset(str,0,sizeof(str));
+	if (copy_from_user(str, buffer, count))
+		return -EFAULT;
+
+	/* Check for S4 bios request */
+	if (!strcmp(str,"4b")) {
+		error = acpi_suspend(4);
+		goto Done;
+	}
+	state = simple_strtoul(str, NULL, 0);
+#ifdef CONFIG_SOFTWARE_SUSPEND
+	if (state == 4) {
+		error = software_suspend();
+		goto Done;
+	}
+#endif
+	error = acpi_suspend(state);
+ Done:
+	return error ? error : count;
+}
+
 static int acpi_system_alarm_seq_show(struct seq_file *seq, void *offset)
 {
 	u32			sec, min, hr;
@@ -294,6 +353,14 @@ acpi_system_write_alarm (
 }
 
 
+static struct file_operations acpi_system_sleep_fops = {
+	.open		= acpi_system_sleep_open_fs,
+	.read		= seq_read,
+	.write		= acpi_system_write_sleep,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
 static struct file_operations acpi_system_alarm_fops = {
 	.open		= acpi_system_alarm_open_fs,
 	.read		= seq_read,
@@ -307,6 +374,12 @@ static int acpi_sleep_proc_init(void)
 {
 	struct proc_dir_entry	*entry = NULL;
 
+	/* 'sleep' [R/W]*/
+	entry = create_proc_entry(ACPI_SYSTEM_FILE_SLEEP,
+				  S_IFREG|S_IRUGO|S_IWUSR, acpi_root_dir);
+	if (entry)
+		entry->proc_fops = &acpi_system_sleep_fops;
+
 	/* 'alarm' [R/W] */
 	entry = create_proc_entry(ACPI_SYSTEM_FILE_ALARM,
 		S_IFREG|S_IRUGO|S_IWUSR, acpi_root_dir);

drivers/acpi/sleep/sleep.h

 
 extern u8 sleep_states[];
-
-extern acpi_status acpi_suspend (u32 state);
+extern int acpi_suspend (u32 state);
 

drivers/base/core.c

@@ -225,28 +225,30 @@ int device_add(struct device *dev)
 		dev->kobj.parent = &parent->kobj;
 
 	if ((error = kobject_add(&dev->kobj)))
-		goto register_done;
-
-	/* now take care of our own registration */
-
+		goto Error;
+	if ((error = device_pm_add(dev)))
+		goto PMError;
+	if ((error = bus_add_device(dev)))
+		goto BusError;
 	down_write(&devices_subsys.rwsem);
 	if (parent)
 		list_add_tail(&dev->node,&parent->children);
 	up_write(&devices_subsys.rwsem);
 
-	bus_add_device(dev);
-
-	device_pm_add(dev);
-
 	/* notify platform of device entry */
 	if (platform_notify)
 		platform_notify(dev);
-
- register_done:
-	if (error && parent)
-		put_device(parent);
+ Done:
 	put_device(dev);
 	return error;
+ BusError:
+	device_pm_remove(dev);
+ PMError:
+	kobject_unregister(&dev->kobj);
+ Error:
+	if (parent)
+		put_device(parent);
+	goto Done;
 }
 
 
@@ -312,8 +314,6 @@ void device_del(struct device * dev)
 {
 	struct device * parent = dev->parent;
 
-	device_pm_remove(dev);
-
 	down_write(&devices_subsys.rwsem);
 	if (parent)
 		list_del_init(&dev->node);
@@ -324,14 +324,11 @@ void device_del(struct device * dev)
 	 */
 	if (platform_notify_remove)
 		platform_notify_remove(dev);
-
 	bus_remove_device(dev);
-
+	device_pm_remove(dev);
 	kobject_del(&dev->kobj);
-
 	if (parent)
 		put_device(parent);
-
 }
 
 /**

drivers/base/power/main.c

@@ -36,12 +36,14 @@ DECLARE_MUTEX(dpm_sem);
 
 static inline void device_pm_hold(struct device * dev)
 {
-	atomic_inc(&dev->power.pm_users);
+	if (dev)
+		atomic_inc(&dev->power.pm_users);
 }
 
 static inline void device_pm_release(struct device * dev)
 {
-	atomic_inc(&dev->power.pm_users);
+	if (dev)
+		atomic_dec(&dev->power.pm_users);
 }
 
 
@@ -61,11 +63,9 @@ static inline void device_pm_release(struct device * dev)
 void device_pm_set_parent(struct device * dev, struct device * parent)
 {
 	struct device * old_parent = dev->power.pm_parent;
-	if (old_parent)
-		device_pm_release(old_parent);
+	device_pm_release(old_parent);
 	dev->power.pm_parent = parent;
-	if (parent)
-		device_pm_hold(parent);
+	device_pm_hold(parent);
 }
 EXPORT_SYMBOL(device_pm_set_parent);
 
@@ -91,6 +91,7 @@ void device_pm_remove(struct device * dev)
 		 dev->bus ? dev->bus->name : "No Bus", dev->kobj.name);
 	down(&dpm_sem);
 	dpm_sysfs_remove(dev);
+	device_pm_release(dev->power.pm_parent);
 	list_del(&dev->power.entry);
 	up(&dpm_sem);
 }

drivers/base/power/power.h

@@ -58,7 +58,8 @@ extern void dpm_sysfs_remove(struct device *);
 /*
  * resume.c 
  */
-extern int dpm_resume(void);
+
+extern void dpm_resume(void);
 extern void dpm_power_up(void);
 extern int resume_device(struct device *);
 

drivers/base/power/resume.c

@@ -28,6 +28,19 @@ int resume_device(struct device * dev)
 }
 
 
+
+void dpm_resume(void)
+{
+	while(!list_empty(&dpm_off)) {
+		struct list_head * entry = dpm_off.next;
+		struct device * dev = to_device(entry);
+		list_del_init(entry);
+		resume_device(dev);
+		list_add_tail(entry,&dpm_active);
+	}
+}
+
+
 /**
  *	device_resume - Restore state of each device in system.
  *
@@ -38,13 +51,7 @@ int resume_device(struct device * dev)
 void device_resume(void)
 {
 	down(&dpm_sem);
-	while(!list_empty(&dpm_off)) {
-		struct list_head * entry = dpm_off.next;
-		struct device * dev = to_device(entry);
-		list_del_init(entry);
-		resume_device(dev);
-		list_add_tail(entry,&dpm_active);
-	}
+	dpm_resume();
 	up(&dpm_sem);
 }
 

drivers/base/power/suspend.c

@@ -81,14 +81,18 @@ int device_suspend(u32 state)
 	while(!list_empty(&dpm_active)) {
 		struct list_head * entry = dpm_active.prev;
 		struct device * dev = to_device(entry);
-		if ((error = suspend_device(dev,state)))
-			goto Error;
+		if ((error = suspend_device(dev,state))) {
+			if (error != -EAGAIN)
+				goto Error;
+			else
+				error = 0;
+		}
 	}
  Done:
 	up(&dpm_sem);
 	return error;
  Error:
-	device_resume();
+	dpm_resume();
 	goto Done;
 }
 

include/asm-i386/suspend.h

@@ -6,11 +6,12 @@
 #include <asm/desc.h>
 #include <asm/i387.h>
 
-static inline void
+static inline int
 arch_prepare_suspend(void)
 {
 	if (!cpu_has_pse)
-		panic("pse required");
+		return -EPERM;
+	return 0;
 }
 
 /* image of the saved processor state */
@@ -38,8 +39,6 @@ struct saved_context {
 extern void save_processor_state(void);
 extern void restore_processor_state(void);
 
-extern int do_magic(int resume);
-
 #ifdef CONFIG_ACPI_SLEEP
 extern unsigned long saved_eip;
 extern unsigned long saved_esp;

include/linux/suspend.h

@@ -53,6 +53,7 @@ extern suspend_pagedir_t *pagedir_nosave __nosavedata;
 extern void do_suspend_lowlevel(int resume);
 extern void do_suspend_lowlevel_s4bios(int resume);
 
+extern int software_suspend(void);
 #else	/* CONFIG_SOFTWARE_SUSPEND */
 static inline int software_suspend(void)
 {

kernel/power/Makefile

 obj-y				:= main.o process.o console.o pm.o
-obj-$(CONFIG_SOFTWARE_SUSPEND)	+= swsusp.o
+obj-$(CONFIG_SOFTWARE_SUSPEND)	+= disk.o swsusp.o
 
 obj-$(CONFIG_MAGIC_SYSRQ)	+= poweroff.o

kernel/power/console.c

@@ -8,7 +8,7 @@
 #include <linux/kbd_kern.h>
 #include "power.h"
 
-static int new_loglevel = 7;
+static int new_loglevel = 10;
 static int orig_loglevel;
 static int orig_fgconsole, orig_kmsg;
 

kernel/power/disk.c

+/*
+ * kernel/power/disk.c - Suspend-to-disk support.
+ *
+ * Copyright (c) 2003 Patrick Mochel
+ * Copyright (c) 2003 Open Source Development Lab
+ * 
+ * This file is release under the GPLv2
+ *
+ */
+
+#define DEBUG
+
+
+#include <linux/suspend.h>
+#include <linux/reboot.h>
+#include <linux/string.h>
+#include <linux/delay.h>
+#include <linux/fs.h>
+#include "power.h"
+
+
+extern u32 pm_disk_mode;
+extern struct pm_ops * pm_ops;
+
+extern int swsusp_save(void);
+extern int swsusp_write(void);
+extern int swsusp_read(void);
+extern int swsusp_restore(void);
+extern int swsusp_free(void);
+
+extern long sys_sync(void);
+
+
+/**
+ *	power_down - Shut machine down for hibernate.
+ *	@mode:		Suspend-to-disk mode
+ *
+ *	Use the platform driver, if configured so, and return gracefully if it
+ *	fails. 
+ *	Otherwise, try to power off and reboot. If they fail, halt the machine,
+ *	there ain't no turning back.
+ */
+
+static int power_down(u32 mode)
+{
+	unsigned long flags;
+	int error = 0;
+
+	local_irq_save(flags);
+	device_power_down(PM_SUSPEND_DISK);
+	switch(mode) {
+	case PM_DISK_PLATFORM:
+		error = pm_ops->enter(PM_SUSPEND_DISK);
+		break;
+	case PM_DISK_SHUTDOWN:
+		printk("Powering off system\n");
+		machine_power_off();
+		break;
+	case PM_DISK_REBOOT:
+		machine_restart(NULL);
+		break;
+	}
+	machine_halt();
+	device_power_up();
+	local_irq_restore(flags);
+	return 0;
+}
+
+
+static int in_suspend __nosavedata = 0;
+
+
+/**
+ *	free_some_memory -  Try to free as much memory as possible
+ *
+ *	... but do not OOM-kill anyone
+ *
+ *	Notice: all userland should be stopped at this point, or 
+ *	livelock is possible.
+ */
+
+static void free_some_memory(void)
+{
+	printk("Freeing memory: ");
+	while (shrink_all_memory(10000))
+		printk(".");
+	printk("|\n");
+	blk_run_queues();
+}
+
+
+static inline void platform_finish(void)
+{
+	if (pm_disk_mode == PM_DISK_PLATFORM) {
+		if (pm_ops && pm_ops->finish)
+			pm_ops->finish(PM_SUSPEND_DISK);
+	}
+}
+
+static void finish(void)
+{
+	device_resume();
+	platform_finish();
+	thaw_processes();
+	pm_restore_console();
+}
+
+
+static int prepare(void)
+{
+	int error;
+
+	pm_prepare_console();
+
+	sys_sync();
+	if (freeze_processes()) {
+		error = -EBUSY;
+		goto Thaw;
+	}
+
+	if (pm_disk_mode == PM_DISK_PLATFORM) {
+		if (pm_ops && pm_ops->prepare) {
+			if ((error = pm_ops->prepare(PM_SUSPEND_DISK)))
+				goto Thaw;
+		}
+	}
+
+	/* Free memory before shutting down devices. */
+	free_some_memory();
+
+	if ((error = device_suspend(PM_SUSPEND_DISK)))
+		goto Finish;
+
+	return 0;
+ Finish:
+	platform_finish();
+ Thaw:
+	thaw_processes();
+	pm_restore_console();
+	return error;
+}
+
+
+/**
+ *	pm_suspend_disk - The granpappy of power management.
+ *	
+ *	If we're going through the firmware, then get it over with quickly.
+ *
+ *	If not, then call swsusp to do it's thing, then figure out how
+ *	to power down the system.
+ */
+
+int pm_suspend_disk(void)
+{
+	int error;
+
+	if ((error = prepare()))
+		return error;
+
+	pr_debug("PM: Attempting to suspend to disk.\n");
+	if (pm_disk_mode == PM_DISK_FIRMWARE)
+		return pm_ops->enter(PM_SUSPEND_DISK);
+
+	pr_debug("PM: snapshotting memory.\n");
+	in_suspend = 1;
+	local_irq_disable();
+	if ((error = swsusp_save()))
+		goto Done;
+
+	pr_debug("PM: writing image.\n");
+
+	/* 
+	 * FIXME: Leftover from swsusp. Are they necessary? 
+	 */
+	mb();
+	barrier();
+
+	error = swsusp_write();
+	if (!error && in_suspend) {
+		error = power_down(pm_disk_mode);
+		pr_debug("PM: Power down failed.\n");
+	} else
+		pr_debug("PM: Image restored successfully.\n");
+	swsusp_free();
+ Done:
+	local_irq_enable();
+	finish();
+	return error;
+}
+
+
+/**
+ *	pm_resume - Resume from a saved image.
+ *
+ *	Called as a late_initcall (so all devices are discovered and 
+ *	initialized), we call swsusp to see if we have a saved image or not.
+ *	If so, we quiesce devices, the restore the saved image. We will 
+ *	return above (in pm_suspend_disk() ) if everything goes well. 
+ *	Otherwise, we fail gracefully and return to the normally 
+ *	scheduled program.
+ *
+ */
+
+static int pm_resume(void)
+{
+	int error;
+
+	pr_debug("PM: Reading swsusp image.\n");
+
+	if ((error = swsusp_read()))
+		goto Done;
+
+	pr_debug("PM: Preparing system for restore.\n");
+
+	if ((error = prepare()))
+		goto Free;
+
+	barrier();
+	mb();
+	local_irq_disable();
+
+	/* FIXME: The following (comment and mdelay()) are from swsusp. 
+	 * Are they really necessary? 
+	 *
+	 * We do not want some readahead with DMA to corrupt our memory, right?
+	 * Do it with disabled interrupts for best effect. That way, if some
+	 * driver scheduled DMA, we have good chance for DMA to finish ;-).
+	 */
+	pr_debug("PM: Waiting for DMAs to settle down.\n");
+	mdelay(1000);
+
+	pr_debug("PM: Restoring saved image.\n");
+	swsusp_restore();
+	local_irq_enable();
+	pr_debug("PM: Restore failed, recovering.n");
+	finish();
+ Free:
+	swsusp_free();
+ Done:
+	pr_debug("PM: Resume from disk failed.\n");
+	return 0;
+}
+
+late_initcall(pm_resume);
+
+
+static char * pm_disk_modes[] = {
+	[PM_DISK_FIRMWARE]	= "firmware",
+	[PM_DISK_PLATFORM]	= "platform",
+	[PM_DISK_SHUTDOWN]	= "shutdown",
+	[PM_DISK_REBOOT]	= "reboot",
+};
+
+/**
+ *	disk - Control suspend-to-disk mode
+ *
+ *	Suspend-to-disk can be handled in several ways. The greatest 
+ *	distinction is who writes memory to disk - the firmware or the OS.
+ *	If the firmware does it, we assume that it also handles suspending 
+ *	the system.
+ *	If the OS does it, then we have three options for putting the system
+ *	to sleep - using the platform driver (e.g. ACPI or other PM registers),
+ *	powering off the system or rebooting the system (for testing). 
+ *
+ *	The system will support either 'firmware' or 'platform', and that is
+ *	known a priori (and encoded in pm_ops). But, the user may choose
+ *	'shutdown' or 'reboot' as alternatives.
+ *
+ *	show() will display what the mode is currently set to. 
+ *	store() will accept one of
+ *
+ *	'firmware'
+ *	'platform'
+ *	'shutdown'
+ *	'reboot'
+ *
+ *	It will only change to 'firmware' or 'platform' if the system
+ *	supports it (as determined from pm_ops->pm_disk_mode).
+ */
+
+static ssize_t disk_show(struct subsystem * subsys, char * buf)
+{
+	return sprintf(buf,"%s\n",pm_disk_modes[pm_disk_mode]);
+}
+
+
+static ssize_t disk_store(struct subsystem * s, const char * buf, size_t n)
+{
+	int error = 0;
+	int i;
+	u32 mode = 0;
+
+	down(&pm_sem);
+	for (i = PM_DISK_FIRMWARE; i < PM_DISK_MAX; i++) {
+		if (!strcmp(buf,pm_disk_modes[i])) {
+			mode = i;
+			break;
+		}
+	}
+	if (mode) {
+		if (mode == PM_DISK_SHUTDOWN || mode == PM_DISK_REBOOT)
+			pm_disk_mode = mode;
+		else {
+			if (pm_ops && pm_ops->enter && 
+			    (mode == pm_ops->pm_disk_mode))
+				pm_disk_mode = mode;
+			else
+				error = -EINVAL;
+		}
+	} else
+		error = -EINVAL;
+
+	pr_debug("PM: suspend-to-disk mode set to '%s'\n",
+		 pm_disk_modes[mode]);
+	up(&pm_sem);
+	return error ? error : n;
+}
+
+power_attr(disk);
+
+static struct attribute * g[] = {
+	&disk_attr.attr,
+	NULL,
+};
+
+
+static struct attribute_group attr_group = {
+	.attrs = g,
+};
+
+
+static int __init pm_disk_init(void)
+{
+	return sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
+}
+
+core_initcall(pm_disk_init);

kernel/power/power.h

@@ -10,34 +10,27 @@
 
 
 #ifdef CONFIG_SOFTWARE_SUSPEND
-extern int swsusp_save(void);
-extern int swsusp_write(void);
-extern int swsusp_read(void);
-extern int swsusp_restore(void);
-extern int swsusp_free(void);
+extern int pm_suspend_disk(void);
+
 #else
-static inline int swsusp_save(void) 
-{
-	return 0;
-}
-static inline int swsusp_write(void)
+static inline int pm_suspend_disk(void)
 {
-	return 0;
-}
-static inline int swsusp_read(void)
-{
-	return 0;
-}
-static inline int swsusp_restore(void)
-{
-	return 0;
-}
-static inline int swsusp_free(void)
-{
-	return 0;
+	return -EPERM;
 }
 #endif
 
+extern struct semaphore pm_sem;
+#define power_attr(_name) \
+static struct subsys_attribute _name##_attr = {	\
+	.attr	= {				\
+		.name = __stringify(_name),	\
+		.mode = 0644,			\
+	},					\
+	.show	= _name##_show,			\
+	.store	= _name##_store,		\
+}
+
+extern struct subsystem power_subsys;
 
 extern int freeze_processes(void);
 extern void thaw_processes(void);

kernel/sys.c

@@ -456,7 +456,7 @@ asmlinkage long sys_reboot(int magic1, int magic2, unsigned int cmd, void __user
 
 #ifdef CONFIG_SOFTWARE_SUSPEND
 	case LINUX_REBOOT_CMD_SW_SUSPEND:
-		if (!pm_suspend(PM_SUSPEND_DISK))
+		if (!software_suspend())
 			break;
 		do_exit(0);
 		break;