[PATCH RFC 2/2] PM / Hibernate: add section for resume options

Sebastian Capella sebastian.capella at linaro.org
Wed Aug 21 15:46:53 EDT 2013

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 <sebastian.capella at linaro.org>
 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

More information about the linux-arm-kernel mailing list