Documentation/power/swsusp.rst

15 				...bye bye root partition.
23    your hardware while system is suspended... well, it was not good idea;
34 Swap partition:
38 Swap file:
47 - If you feel ACPI works pretty well on your system, you might try::
51 - If you would like to write hibernation image to swap and then suspend
56 - If you have SATA disks, you'll need recent kernels with SATA suspend
58   are built into kernel -- not modules. [There's way to make
68 - The resume process checks for the presence of the resume device,
72 - The resume process may be triggered in two ways:
79      the init script by using the /sys/power/resume file.  It is vital
81      read-only) otherwise data may be corrupted.
87 Last revised: 2003-10-20 by Pavel Machek
90 -------------------------
93 saves the state of the machine to a filesystem or to a partition and switches
102 powerdowns.  You must explicitly specify the swap partition to resume from with
108 In the meantime while the system is suspended you should not add/remove any
124   echo 5 > /proc/acpi/sleep       # for shutdown unfriendly the system
163     between 0-640KB. That way, I'd have to make sure that 0-640KB is free
181   suspend-to-disk which is available as separate patches for 2.4 and 2.6
196   kernel threads are controlled during hibernation or system-wide suspend (on
197   some architectures).  See freezing-of-tasks.txt for details.
219   it's useless for suspend-to-disk. (And I do not see how you could use
220   it for suspend-to-ram, I hope you do not want that).
241   complicated code. (And I have not yet introduce details like system
257   After resuming, system is paging heavily, leading to very bad interactivity.
262     cat /proc/[0-9]*/maps | grep / | sed 's:.* /:/:' | sort -u | while read file
264       test -f "$file" && cat "$file" > /dev/null
267   after resume. swapoff -a; swapon -a may also be useful.
271   during system suspend?
279       running system, user asks for suspend-to-disk
301       running system, user asks for suspend-to-disk
304       but with resume-from-initrd, no one knows)
313       resume(): devices are woken up so that system can continue
321   First of all: it is not a replacement for dm-crypt encrypted swap.
333   on disk virtually forever. Thus it can happen that your system gets
344   partition used for suspend as early as possible during regular
349   system is shut down or suspended. Additionally use the encrypted
354   Can I suspend to a swap file?
359   file cannot be initiated from an initrd or initramfs image.  See
360   swsusp-and-swap-files.txt for details.
363   Is there a maximum system RAM size that is supported by swsusp?
369   Does swsusp (to disk) use only one swap partition or can it use
373   Only one swap partition, sorry.
377   (over half of the total system RAM), is it correct that it is likely
382   it. Just prepare big enough swap partition.
385   What information is useful for debugging suspend-to-disk problems?
397   How can distributions ship a swsusp-supporting kernel with modular
402   /sys/power/resume file from initrd. Be sure not to mount
403   anything, not even read-only mount, or you are going to lose your
410   If you want to see any non-error kernel messages on the virtual
419 	if [ $LOGLEVEL -lt 5 ]; then
425         echo -n disk > /sys/power/state
431 	if [ $RET -ne 0 -a $IMG_SZ -ne 0 ]; then # try again with minimal image size
433                 echo -n disk > /sys/power/state
448   In fact, even with "-o sync" you can lose data if your programs have
453   to disconnecting all USB devices attached to your system.
455   Your system might well support low-power modes for its USB controllers
456   while the system is asleep, maintaining the connection, using true sleep
457   modes like "suspend-to-RAM" or "standby".  (Don't write "disk" to the
458   /sys/power/state file; write "standby" or "mem".)  We've not seen any
464   mounted filesystem.  That's true even when your system is asleep!  The
469   There is a work-around for this problem.  For more information, see
470   Documentation/driver-api/usb/persist.rst.
473   Can I suspend-to-disk using a swap partition under LVM?
481     echo -n "$major:$minor" > /sys/power/resume
496   for 2.6.15 (by saving more data we can get more responsive system
502   slow, take a look at suspend.sf.net -- userland suspend is faster and