[PATCH] swsusp: debugging
Add a swsusp debugging mode. This does everything that's needed for a suspend
except for actually suspending. So we can look in the log messages and work
out a) what code is being slow and b) which drivers are misbehaving.
(1)
# echo testproc > /sys/power/disk
# echo disk > /sys/power/state
This should turn off the non-boot CPU, freeze all processes, wait for 5
seconds and then thaw the processes and the CPU.
(2)
# echo test > /sys/power/disk
# echo disk > /sys/power/state
This should turn off the non-boot CPU, freeze all processes, shrink
memory, suspend all devices, wait for 5 seconds, resume the devices etc.
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Stefan Seyfried <seife@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/Documentation/ABI/testing/sysfs-power b/Documentation/ABI/testing/sysfs-power
index d882f80..dcff4d0 100644
--- a/Documentation/ABI/testing/sysfs-power
+++ b/Documentation/ABI/testing/sysfs-power
@@ -21,7 +21,7 @@
these states.
What: /sys/power/disk
-Date: August 2006
+Date: September 2006
Contact: Rafael J. Wysocki <rjw@sisk.pl>
Description:
The /sys/power/disk file controls the operating mode of the
@@ -39,6 +39,19 @@
'reboot' - the memory image will be saved by the kernel and
the system will be rebooted.
+ Additionally, /sys/power/disk can be used to turn on one of the
+ two testing modes of the suspend-to-disk mechanism: 'testproc'
+ or 'test'. If the suspend-to-disk mechanism is in the
+ 'testproc' mode, writing 'disk' to /sys/power/state will cause
+ the kernel to disable nonboot CPUs and freeze tasks, wait for 5
+ seconds, unfreeze tasks and enable nonboot CPUs. If it is in
+ the 'test' mode, writing 'disk' to /sys/power/state will cause
+ the kernel to disable nonboot CPUs and freeze tasks, shrink
+ memory, suspend devices, wait for 5 seconds, resume devices,
+ unfreeze tasks and enable nonboot CPUs. Then, we are able to
+ look in the log messages and work out, for example, which code
+ is being slow and which device drivers are misbehaving.
+
The suspend-to-disk method may be chosen by writing to this
file one of the accepted strings:
@@ -46,6 +59,8 @@
'platform'
'shutdown'
'reboot'
+ 'testproc'
+ 'test'
It will only change to 'firmware' or 'platform' if the system
supports that.