1====================================================
2Testing suspend and resume support in device drivers
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4
5	(C) 2007 Rafael J. Wysocki <rjw@sisk.pl>, GPL
6
71. Preparing the test system
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9
10Unfortunately, to effectively test the support for the system-wide suspend and
11resume transitions in a driver, it is necessary to suspend and resume a fully
12functional system with this driver loaded.  Moreover, that should be done
13several times, preferably several times in a row, and separately for hibernation
14(aka suspend to disk or STD) and suspend to RAM (STR), because each of these
15cases involves slightly different operations and different interactions with
16the machine's BIOS.
17
18Of course, for this purpose the test system has to be known to suspend and
19resume without the driver being tested.  Thus, if possible, you should first
20resolve all suspend/resume-related problems in the test system before you start
21testing the new driver.  Please see Documentation/power/basic-pm-debugging.rst
22for more information about the debugging of suspend/resume functionality.
23
242. Testing the driver
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26
27Once you have resolved the suspend/resume-related problems with your test system
28without the new driver, you are ready to test it:
29
30a) Build the driver as a module, load it and try the test modes of hibernation
31   (see: Documentation/power/basic-pm-debugging.rst, 1).
32
33b) Load the driver and attempt to hibernate in the "reboot", "shutdown" and
34   "platform" modes (see: Documentation/power/basic-pm-debugging.rst, 1).
35
36c) Compile the driver directly into the kernel and try the test modes of
37   hibernation.
38
39d) Attempt to hibernate with the driver compiled directly into the kernel
40   in the "reboot", "shutdown" and "platform" modes.
41
42e) Try the test modes of suspend (see:
43   Documentation/power/basic-pm-debugging.rst, 2).  [As far as the STR tests are
44   concerned, it should not matter whether or not the driver is built as a
45   module.]
46
47f) Attempt to suspend to RAM using the s2ram tool with the driver loaded
48   (see: Documentation/power/basic-pm-debugging.rst, 2).
49
50Each of the above tests should be repeated several times and the STD tests
51should be mixed with the STR tests.  If any of them fails, the driver cannot be
52regarded as suspend/resume-safe.
53