2013-08-21 20:09:32

by Sebastian Capella

[permalink] [raw]
Subject:

From: Sebastian Capella <[email protected]>
Subject: [PATCH RFC 2/2] PM / Hibernate: add section for resume options

Expand the existing documentation to explicitly list the options for
resuming a hibernation image, including the manual resume option which
can be used from the initrd or initramfs and the kernel init resume.

Signed-off-by: Sebastian Capella <[email protected]>
---
Documentation/power/swsusp.txt | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/Documentation/power/swsusp.txt b/Documentation/power/swsusp.txt
index 0b4b63e..079160e 100644
--- a/Documentation/power/swsusp.txt
+++ b/Documentation/power/swsusp.txt
@@ -50,6 +50,19 @@ echo N > /sys/power/image_size

before suspend (it is limited to 500 MB by default).

+. The resume process checks for the presence of the resume device,
+if found, it then checks the contents for the hibernation image signature.
+If both are found, it resumes the hibernation image.
+
+. The resume process may be triggered in two ways:
+ 1) During lateinit: If resume=/dev/your_swap_partition is specified on
+ the kernel command line, lateinit runs the resume process. If the
+ resume device has not been probed yet, the resume process fails and
+ bootup continues.
+ 2) Manually from an initrd or initramfs: May be run from
+ the init script by using the /sys/power/resume file. It is vital
+ that this be done prior to remounting any filesystems (even as
+ read-only) otherwise data may be corrupted.

Article about goals and implementation of Software Suspend for Linux
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -326,7 +339,7 @@ Q: How can distributions ship a swsusp-supporting kernel with modular
disk drivers (especially SATA)?

A: Well, it can be done, load the drivers, then do echo into
-/sys/power/disk/resume file from initrd. Be sure not to mount
+/sys/power/resume file from initrd. Be sure not to mount
anything, not even read-only mount, or you are going to lose your
data.

--
1.7.9.5