diff options
Diffstat (limited to 'Documentation/power/swsusp.txt')
| -rw-r--r-- | Documentation/power/swsusp.txt | 45 |
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. |