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Diffstat (limited to 'Documentation/power/swsusp.txt')
| -rw-r--r-- | Documentation/power/swsusp.txt | 21 |
1 files changed, 7 insertions, 14 deletions
diff --git a/Documentation/power/swsusp.txt b/Documentation/power/swsusp.txt index 5b8d6953f05e..aea7e9209667 100644 --- a/Documentation/power/swsusp.txt +++ b/Documentation/power/swsusp.txt @@ -140,21 +140,11 @@ 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. -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"? @@ -393,6 +383,9 @@ 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. +There is a work-around for this problem. For more information, see +Documentation/usb/persist.txt. + 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 |