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authorRafael J. Wysocki <rjw@sisk.pl>2006-11-02 22:07:19 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-11-03 12:27:58 -0800
commitb918f6e62cd46774f9fc0a3fbba6bd10ad85ee14 (patch)
treed73dc0e8823c8445d84701cc3d527e0e34494a32 /Documentation/power
parent90d53909443b3986569b38ef145f09ea2359af75 (diff)
downloadlwn-b918f6e62cd46774f9fc0a3fbba6bd10ad85ee14.tar.gz
lwn-b918f6e62cd46774f9fc0a3fbba6bd10ad85ee14.zip
[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>
Diffstat (limited to 'Documentation/power')
-rw-r--r--Documentation/power/interface.txt13
1 files changed, 13 insertions, 0 deletions
diff --git a/Documentation/power/interface.txt b/Documentation/power/interface.txt
index a66bec222b16..74311d7e0f3c 100644
--- a/Documentation/power/interface.txt
+++ b/Documentation/power/interface.txt
@@ -30,6 +30,17 @@ testing). The system will support either 'firmware' or 'platform', and
that is known a priori. But, the user may choose 'shutdown' or
'reboot' as alternatives.
+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.
+
Reading from this file will display what the mode is currently set
to. Writing to this file will accept one of
@@ -37,6 +48,8 @@ to. Writing to this file will accept one of
'platform'
'shutdown'
'reboot'
+ 'testproc'
+ 'test'
It will only change to 'firmware' or 'platform' if the system supports
it.