Commit eb57c1cf authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Len Brown
Browse files

Hibernation: Rework platform support ioctls (rev. 2) 



Modify the hibernation userland interface by adding two new ioctls to it,
SNAPSHOT_PLATFORM_SUPPORT and SNAPSHOT_POWER_OFF, that can be used,
respectively, to switch the hibernation platform support on/off and to make the
kernel transition the system to the hibernation state (eg. ACPI S4) using the
platform (eg. ACPI) driver.

These ioctls are intended to replace the misdesigned SNAPSHOT_PMOPS ioctl,
which from now is regarded as obsolete and will be removed in the future.

Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
Acked-by: default avatarPavel Machek <pavel@ucw.cz>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent af508b34

Documentation/power/userland-swsusp.txt

+6 −18
Original line number Diff line number Diff line
@@ -85,6 +85,12 @@ SNAPSHOT_SET_SWAP_AREA - set the resume partition and the offset (in <PAGE_SIZE> 
	recommended to always use this call, because the code to set the resume

	partition may be removed from future kernels



SNAPSHOT_PLATFORM_SUPPORT - enable/disable the hibernation platform support,

	depending on the argument value (enable, if the argument is nonzero)



SNAPSHOT_POWER_OFF - make the kernel transition the system to the hibernation

	state (eg. ACPI S4) using the platform (eg. ACPI) driver



SNAPSHOT_S2RAM - suspend to RAM; using this call causes the kernel to

	immediately enter the suspend-to-RAM state, so this call must always

	be preceded by the SNAPSHOT_FREEZE call and it is also necessary
@@ -95,24 +101,6 @@ SNAPSHOT_S2RAM - suspend to RAM; using this call causes the kernel to 
	to resume the system from RAM if there's enough battery power or restore

	its state on the basis of the saved suspend image otherwise)



SNAPSHOT_PMOPS - enable the usage of the hibernation_ops->prepare,

	hibernate_ops->enter and hibernation_ops->finish methods (the in-kernel

	swsusp knows these as the "platform method") which are needed on many

	machines to (among others) speed up the resume by letting the BIOS skip

	some steps or to let the system recognise the correct state of the

	hardware after the resume (in particular on many machines this ensures

	that unplugged AC adapters get correctly detected and that kacpid does

	not run wild after the resume).  The last ioctl() argument can take one

	of the three values, defined in kernel/power/power.h:

	PMOPS_PREPARE - make the kernel carry out the

		hibernation_ops->prepare() operation

	PMOPS_ENTER - make the kernel power off the system by calling

		hibernation_ops->enter()

	PMOPS_FINISH - make the kernel carry out the

		hibernation_ops->finish() operation

	Note that the actual constants are misnamed because they surface

	internal kernel implementation details that have changed.



The device's read() operation can be used to transfer the snapshot image from

the kernel.  It has the following limitations:

- you cannot read() more than one virtual memory page at a time

kernel/power/power.h

+3 −6
Original line number Diff line number Diff line
@@ -156,15 +156,12 @@ struct resume_swap_area { 
#define SNAPSHOT_FREE_SWAP_PAGES	_IO(SNAPSHOT_IOC_MAGIC, 9)

#define SNAPSHOT_SET_SWAP_FILE		_IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int)

#define SNAPSHOT_S2RAM			_IO(SNAPSHOT_IOC_MAGIC, 11)

#define SNAPSHOT_PMOPS			_IOW(SNAPSHOT_IOC_MAGIC, 12, unsigned int)

#define SNAPSHOT_SET_SWAP_AREA		_IOW(SNAPSHOT_IOC_MAGIC, 13, \

							struct resume_swap_area)

#define SNAPSHOT_GET_IMAGE_SIZE		_IOR(SNAPSHOT_IOC_MAGIC, 14, loff_t)

#define SNAPSHOT_IOC_MAXNR	14



#define PMOPS_PREPARE	1

#define PMOPS_ENTER	2

#define PMOPS_FINISH	3

#define SNAPSHOT_PLATFORM_SUPPORT	_IO(SNAPSHOT_IOC_MAGIC, 15)

#define SNAPSHOT_POWER_OFF		_IO(SNAPSHOT_IOC_MAGIC, 16)

#define SNAPSHOT_IOC_MAXNR	16



/* If unset, the snapshot device cannot be open. */

extern atomic_t snapshot_device_available;

kernel/power/user.c

+29 −10
Original line number Diff line number Diff line
@@ -28,6 +28,18 @@ 


#include "power.h"



/*

 * NOTE: The SNAPSHOT_PMOPS ioctl is obsolete and will be removed in the

 * future.  It is only preserved here for compatibility with existing userland

 * utilities.

 */

#define SNAPSHOT_PMOPS		_IOW(SNAPSHOT_IOC_MAGIC, 12, unsigned int)



#define PMOPS_PREPARE	1

#define PMOPS_ENTER	2

#define PMOPS_FINISH	3





#define SNAPSHOT_MINOR	231



static struct snapshot_data {
@@ -36,7 +48,7 @@ static struct snapshot_data { 
	int mode;

	char frozen;

	char ready;

	char platform_suspend;

	char platform_support;

} snapshot_state;



atomic_t snapshot_device_available = ATOMIC_INIT(1);
@@ -70,7 +82,7 @@ static int snapshot_open(struct inode *inode, struct file *filp) 
	}

	data->frozen = 0;

	data->ready = 0;

	data->platform_suspend = 0;

	data->platform_support = 0;



	return 0;

}
@@ -183,7 +195,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp, 
			error = -EPERM;

			break;

		}

		error = hibernation_snapshot(data->platform_suspend);

		error = hibernation_snapshot(data->platform_support);

		if (!error)

			error = put_user(in_suspend, (unsigned int __user *)arg);

		if (!error)
@@ -197,7 +209,7 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp, 
			error = -EPERM;

			break;

		}

		error = hibernation_restore(data->platform_suspend);

		error = hibernation_restore(data->platform_support);

		break;



	case SNAPSHOT_FREE:
@@ -285,26 +297,33 @@ static int snapshot_ioctl(struct inode *inode, struct file *filp, 
		mutex_unlock(&pm_mutex);

		break;



	case SNAPSHOT_PMOPS:

	case SNAPSHOT_PLATFORM_SUPPORT:

		data->platform_support = !!arg;

		break;



	case SNAPSHOT_POWER_OFF:

		if (data->platform_support)

			error = hibernation_platform_enter();

		break;



	case SNAPSHOT_PMOPS: /* This ioctl is deprecated */

		error = -EINVAL;



		switch (arg) {



		case PMOPS_PREPARE:

			data->platform_suspend = 1;

			data->platform_support = 1;

			error = 0;

			break;



		case PMOPS_ENTER:

			if (data->platform_suspend)

			if (data->platform_support)

				error = hibernation_platform_enter();



			break;



		case PMOPS_FINISH:

			if (data->platform_suspend)

			if (data->platform_support)

				error = 0;



			break;



		default:

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