* but it will probably only crash.
*
* (*) suspend/resume support is needed to make it safe.
- *
- * If you have any filesystems on USB devices mounted before suspend,
- * they won't be accessible after resume and you may lose data, as though
- * you have unplugged the USB devices with mounted filesystems on them
- * (see the FAQ below for details).
You need to append resume=/dev/your_swap_partition to kernel command
line. Then you suspend by
echo platform > /sys/power/disk; echo disk > /sys/power/state
-. If you have SATA disks, you'll need recent kernels with SATA suspend
-support. For suspend and resume to work, make sure your disk drivers
-are built into kernel -- not modules. [There's way to make
-suspend/resume with modular disk drivers, see FAQ, but you probably
-should not do that.]
-
If you want to limit the suspend image size to N bytes, do
echo N > /sys/power/image_size
before suspend (it is limited to 500 MB by default).
+Encrypted suspend image:
+------------------------
+If you want to store your suspend image encrypted with a temporary
+key to prevent data gathering after resume you must compile
+crypto and the aes algorithm into the kernel - modules won't work
+as they cannot be loaded at resume time.
+
Article about goals and implementation of Software Suspend for Linux
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
usually does the trick. Then it is good idea to try with latest
vanilla kernel.
-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
-anything, not even read-only mount, or you are going to lose your
-data.
-
-Q: How do I make suspend more verbose?
-
-A: If you want to see any non-error kernel messages on the virtual
-terminal the kernel switches to during suspend, you have to set the
-kernel console loglevel to at least 5, for example by doing
-
- echo 5 > /proc/sys/kernel/printk
-
-Q: Is this true that if I have a mounted filesystem on a USB device and
-I suspend to disk, I can lose data unless the filesystem has been mounted
-with "sync"?
-
-A: That's right. It depends on your hardware, and it could be true even for
-suspend-to-RAM. In fact, even with "-o sync" you can lose data if your
-programs have information in buffers they haven't written out to disk.
-
-If you're lucky, your hardware will support low-power modes for USB
-controllers while the system is asleep. Lots of hardware doesn't,
-however. Shutting off the power to a USB controller is equivalent to
-unplugging all the attached devices.
-
-Remember that it's always a bad idea to unplug a disk drive containing a
-mounted filesystem. With USB that's true even when your system is asleep!
-The safest thing is to unmount all USB-based filesystems before suspending
-and remount them after resuming.
git://git.onelab.eu / linux-2.6.git / blobdiff