diff options
Diffstat (limited to 'Documentation/power/swsusp.txt')
| -rw-r--r-- | Documentation/power/swsusp.txt | 18 |
1 files changed, 4 insertions, 14 deletions
diff --git a/Documentation/power/swsusp.txt b/Documentation/power/swsusp.txt index 152b510d1bbb..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 | |||
| 140 | website, and not to the Linux Kernel Mailing List. We are working | 140 | website, and not to the Linux Kernel Mailing List. We are working |
| 141 | toward merging suspend2 into the mainline kernel. | 141 | toward merging suspend2 into the mainline kernel. |
| 142 | 142 | ||
| 143 | Q: A kernel thread must voluntarily freeze itself (call 'refrigerator'). | 143 | Q: What is the freezing of tasks and why are we using it? |
| 144 | I found some kernel threads that don't do it, and they don't freeze | ||
| 145 | so the system can't sleep. Is this a known behavior? | ||
| 146 | |||
| 147 | A: All such kernel threads need to be fixed, one by one. Select the | ||
| 148 | place where the thread is safe to be frozen (no kernel semaphores | ||
| 149 | should be held at that point and it must be safe to sleep there), and | ||
| 150 | add: | ||
| 151 | |||
| 152 | try_to_freeze(); | ||
| 153 | |||
| 154 | If the thread is needed for writing the image to storage, you should | ||
| 155 | instead set the PF_NOFREEZE process flag when creating the thread (and | ||
| 156 | be very careful). | ||
| 157 | 144 | ||
| 145 | A: The freezing of tasks is a mechanism by which user space processes and some | ||
| 146 | kernel threads are controlled during hibernation or system-wide suspend (on some | ||
| 147 | architectures). See freezing-of-tasks.txt for details. | ||
| 158 | 148 | ||
| 159 | Q: What is the difference between "platform" and "shutdown"? | 149 | Q: What is the difference between "platform" and "shutdown"? |
| 160 | 150 | ||