linux 2.6.16.38 w/ vs2.0.3-rc1

[linux-2.6.git] / Documentation / power / swsusp.txt

diff --git a/Documentation/power/swsusp.txt b/Documentation/power/swsusp.txt
index d7814a1..b28b7f0 100644 (file)
--- a/Documentation/power/swsusp.txt
+++ b/Documentation/power/swsusp.txt
@@ -17,11 +17,6 @@ Some warnings, first.
  * but it will probably only crash.
  *
  * (*) suspend/resume support is needed to make it safe.
  * 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
 
 You need to append resume=/dev/your_swap_partition to kernel command
 line. Then you suspend by


@@ -32,18 +27,19 @@ echo shutdown > /sys/power/disk; echo disk > /sys/power/state
 
 echo platform > /sys/power/disk; echo disk > /sys/power/state
 
 
 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).
 
 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
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Article about goals and implementation of Software Suspend for Linux
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


@@ -337,37 +333,4 @@ init=/bin/bash, then swapon and starting suspend sequence manually
 usually does the trick. Then it is good idea to try with latest
 vanilla kernel.
 
 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.