Hibernation: Rework platform support ioctls (rev. 2)

[linux-2.6] / Documentation / power / userland-swsusp.txt

diff --git a/Documentation/power/userland-swsusp.txt b/Documentation/power/userland-swsusp.txt
index e00c6cf09e85aad17e587f0ac9d19d0a543a4cad..381e9c0fb9d69ef97c7bc5a4dcf4ef7f43155a44 100644 (file)
--- a/Documentation/power/userland-swsusp.txt
+++ b/Documentation/power/userland-swsusp.txt
@@ -54,6 +54,8 @@ SNAPSHOT_SET_IMAGE_SIZE - set the preferred maximum size of the image
        this number, but if it turns out to be impossible, the kernel will
        create the smallest image possible)
 
+SNAPSHOT_GET_IMAGE_SIZE - return the actual size of the hibernation image
+
 SNAPSHOT_AVAIL_SWAP - return the amount of available swap in bytes (the last
        argument should be a pointer to an unsigned int variable that will
        contain the result if the call is successful).
@@ -83,6 +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
@@ -93,24 +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
@@ -136,13 +126,9 @@ required, as they can use, for example, a special (blank) suspend partition or
 a file on a partition that is unmounted before SNAPSHOT_ATOMIC_SNAPSHOT and
 mounted afterwards.
 
-These utilities SHOULD NOT make any assumptions regarding the ordering of
-data within the snapshot image, except for the image header that MAY be
-assumed to start with an swsusp_info structure, as specified in
-kernel/power/power.h.  This structure MAY be used by the userland utilities
-to obtain some information about the snapshot image, such as the size
-of the snapshot image, including the metadata and the header itself,
-contained in the .size member of swsusp_info.
+These utilities MUST NOT make any assumptions regarding the ordering of
+data within the snapshot image.  The contents of the image are entirely owned
+by the kernel and its structure may be changed in future kernel releases.
 
 The snapshot image MUST be written to the kernel unaltered (ie. all of the image
 data, metadata and header MUST be written in _exactly_ the same amount, form