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Commit bc6a0cbd authored by Pavel Machek's avatar Pavel Machek Committed by Rafael J. Wysocki
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PM / Hibernate: document open(/dev/snapshot) side effects 



Opening and closing /dev/snapshot causes the kernel to carry out
some hibernate preparations that should be documented.

[rjw: Added the changelog.]

Signed-off-by: default avatarPavel Machek <pavel@ucw.cz>
Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
parent c92445fa

Documentation/power/userland-swsusp.txt

+4 −0
Original line number Diff line number Diff line
@@ -24,6 +24,10 @@ assumed to be in the resume mode. The device cannot be open for simultaneous 
reading and writing.  It is also impossible to have the device open more than

once at a time.



Even opening the device has side effects. Data structures are

allocated, and PM_HIBERNATION_PREPARE / PM_RESTORE_PREPARE chains are

called.



The ioctl() commands recognized by the device are:



SNAPSHOT_FREEZE - freeze user space processes (the current process is