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authorPavel Machek <pavel@ucw.cz>2006-06-23 02:04:50 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-23 07:43:00 -0700
commite084dbd3a995f99f5444a9046e66d93c1b92c348 (patch)
treeeda6d7537af3fb36c3152f2ff3942fc4d5790efa /Documentation/power/swsusp.txt
parent55b2355eefc2f160246226d4d69fed431173a4d5 (diff)
[PATCH] swsusp: documentation updates
Update documentation a bit, add more machines to video.txt list. Signed-off-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'Documentation/power/swsusp.txt')
-rw-r--r--Documentation/power/swsusp.txt45
1 files changed, 42 insertions, 3 deletions
diff --git a/Documentation/power/swsusp.txt b/Documentation/power/swsusp.txt
index 516c5019013..823b2cf6e3d 100644
--- a/Documentation/power/swsusp.txt
+++ b/Documentation/power/swsusp.txt
@@ -350,9 +350,34 @@ 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
+kernel console loglevel to at least 4 (KERN_WARNING), for example by
+doing
+
+ # save the old loglevel
+ read LOGLEVEL DUMMY < /proc/sys/kernel/printk
+ # set the loglevel so we see the progress bar.
+ # if the level is higher than needed, we leave it alone.
+ if [ $LOGLEVEL -lt 5 ]; then
+ echo 5 > /proc/sys/kernel/printk
+ fi
+
+ IMG_SZ=0
+ read IMG_SZ < /sys/power/image_size
+ echo -n disk > /sys/power/state
+ RET=$?
+ #
+ # the logic here is:
+ # if image_size > 0 (without kernel support, IMG_SZ will be zero),
+ # then try again with image_size set to zero.
+ if [ $RET -ne 0 -a $IMG_SZ -ne 0 ]; then # try again with minimal image size
+ echo 0 > /sys/power/image_size
+ echo -n disk > /sys/power/state
+ RET=$?
+ fi
+
+ # restore previous loglevel
+ echo $LOGLEVEL > /proc/sys/kernel/printk
+ exit $RET
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
@@ -380,3 +405,17 @@ safest thing is to unmount all filesystems on removable media (such USB,
Firewire, CompactFlash, MMC, external SATA, or even IDE hotplug bays)
before suspending; then remount them after resuming.
+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
+2.6.15. Any idea for why that might happen or how can I speed it up?
+
+A: This is because the size of the suspend image is now greater than
+for 2.6.15 (by saving more data we can get more responsive system
+after resume).
+
+There's the /sys/power/image_size knob that controls the size of the
+image. If you set it to 0 (eg. by echo 0 > /sys/power/image_size as
+root), the 2.6.15 behavior should be restored. If it is still too
+slow, take a look at suspend.sf.net -- userland suspend is faster and
+supports LZF compression to speed it up further.