From 1c93669929f0f52e7033c6529274dce8cc46a9a1 Mon Sep 17 00:00:00 2001 From: Sebastian Capella Date: Mon, 26 Aug 2013 14:54:49 -0700 Subject: [PATCH] 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 Acked-by: Rob Landley Signed-off-by: Jiri Kosina --- 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 0b4b63e7e9b6..079160e22bcc 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.