Documentation/power/freezing-of-tasks.rst

7 I. What is the freezing of tasks?
10 The freezing of tasks is a mechanism by which user space processes and some
27 whether the system is to undergo a freezing operation. And freeze_processes()
62 initiated a freezing operation, the freezing of tasks will fail and the entire
73 Rationale behind the functions dealing with freezing and thawing of tasks
81     kernel threads without freezing userspace tasks
104 Generally speaking, there is a couple of reasons to use the freezing of tasks:
126    freezing them earlier. [Of course, this also means that device drivers
133    example, be troublesome and without the freezing of tasks we would need some
136 Although Linus Torvalds doesn't like the freezing of tasks, he said this in one
150 freezing user threads I don't find really objectionable."
160 4. Another reason for freezing tasks is to prevent user space processes from
165    is quite difficult to achieve without the freezing of tasks.  Consider,
171 V. Are there any problems related to the freezing of tasks?
176 First of all, the freezing of kernel threads may be tricky if they depend one
182 Second, there are the following two problems related to the freezing of user
197 There are also problems that the freezing of tasks tends to expose, although
201 at this point.  So, seemingly, the failure is due to the freezing of tasks.
204 request_firmware() will fail regardless of whether or not the freezing of tasks
205 is used.  Consequently, the problem is not really related to the freezing of
213 VI. Are there any precautions to be taken to prevent freezing failures?
226 mutex_[un]lock(&system_transition_mutex) since that could lead to freezing
231 freezing failure.
234 since they ask the freezer to skip freezing this task, since it is anyway
238 mutex_[un]lock(&system_transition_mutex). That would prevent freezing failures.