Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6

[pandora-kernel.git] / Documentation / power / swsusp.txt

diff --git a/Documentation/power/swsusp.txt b/Documentation/power/swsusp.txt
index 152b510..ea71889 100644 (file)
--- a/Documentation/power/swsusp.txt
+++ b/Documentation/power/swsusp.txt
@@ -66,7 +66,8 @@ swsusp saves the state of the machine into active swaps and then reboots or
 powerdowns.  You must explicitly specify the swap partition to resume from with
 ``resume='' kernel option. If signature is found it loads and restores saved
 state. If the option ``noresume'' is specified as a boot parameter, it skips
 powerdowns.  You must explicitly specify the swap partition to resume from with
 ``resume='' kernel option. If signature is found it loads and restores saved
 state. If the option ``noresume'' is specified as a boot parameter, it skips

-the resuming.
+the resuming.  If the option ``hibernate=nocompress'' is specified as a boot
+parameter, it saves hibernation image without compression.

 
 In the meantime while the system is suspended you should not add/remove any
 of the hardware, write to the filesystems, etc.
 
 In the meantime while the system is suspended you should not add/remove any
 of the hardware, write to the filesystems, etc.


@@ -140,21 +141,11 @@ should be sent to the mailing list available through the suspend2
 website, and not to the Linux Kernel Mailing List. We are working
 toward merging suspend2 into the mainline kernel.
 
 website, and not to the Linux Kernel Mailing List. We are working
 toward merging suspend2 into the mainline kernel.
 

-Q: A kernel thread must voluntarily freeze itself (call 'refrigerator').
-I found some kernel threads that don't do it, and they don't freeze
-so the system can't sleep. Is this a known behavior?
-
-A: All such kernel threads need to be fixed, one by one. Select the
-place where the thread is safe to be frozen (no kernel semaphores
-should be held at that point and it must be safe to sleep there), and
-add:
-
-       try_to_freeze();
-
-If the thread is needed for writing the image to storage, you should
-instead set the PF_NOFREEZE process flag when creating the thread (and
-be very careful).
+Q: What is the freezing of tasks and why are we using it?

 
 

+A: The freezing of tasks is a mechanism by which user space processes and some
+kernel threads are controlled during hibernation or system-wide suspend (on some
+architectures).  See freezing-of-tasks.txt for details.

 
 Q: What is the difference between "platform" and "shutdown"?
 
 
 Q: What is the difference between "platform" and "shutdown"?
 


@@ -396,6 +387,11 @@ before suspending; then remount them after resuming.
 There is a work-around for this problem.  For more information, see
 Documentation/usb/persist.txt.
 
 There is a work-around for this problem.  For more information, see
 Documentation/usb/persist.txt.
 

+Q: Can I suspend-to-disk using a swap partition under LVM?
+
+A: No. You can suspend successfully, but you'll not be able to
+resume. uswsusp should be able to work with LVM. See suspend.sf.net.
+

 Q: I upgraded the kernel from 2.6.15 to 2.6.16. Both kernels were
 compiled with the similar configuration files. Anyway I found that
 suspend to disk (and resume) is much slower on 2.6.16 compared to
 Q: I upgraded the kernel from 2.6.15 to 2.6.16. Both kernels were
 compiled with the similar configuration files. Anyway I found that
 suspend to disk (and resume) is much slower on 2.6.16 compared to