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5b795202 RW |
1 | Testing suspend and resume support in device drivers |
2 | (C) 2007 Rafael J. Wysocki <rjw@sisk.pl>, GPL | |
3 | ||
4 | 1. Preparing the test system | |
5 | ||
6 | Unfortunately, to effectively test the support for the system-wide suspend and | |
7 | resume transitions in a driver, it is necessary to suspend and resume a fully | |
8 | functional system with this driver loaded. Moreover, that should be done | |
9 | several times, preferably several times in a row, and separately for the suspend | |
10 | to disk (STD) and the suspend to RAM (STR) transitions, because each of these | |
11 | cases involves different ordering of operations and different interactions with | |
12 | the machine's BIOS. | |
13 | ||
14 | Of course, for this purpose the test system has to be known to suspend and | |
15 | resume without the driver being tested. Thus, if possible, you should first | |
16 | resolve all suspend/resume-related problems in the test system before you start | |
17 | testing the new driver. Please see Documents/power/basic-pm-debugging.txt for | |
18 | more information about the debugging of suspend/resume functionality. | |
19 | ||
20 | 2. Testing the driver | |
21 | ||
22 | Once you have resolved the suspend/resume-related problems with your test system | |
23 | without the new driver, you are ready to test it: | |
24 | ||
25 | a) Build the driver as a module, load it and try the STD in the test mode (see: | |
26 | Documents/power/basic-pm-debugging.txt, 1a)). | |
27 | ||
28 | b) Load the driver and attempt to suspend to disk in the "reboot", "shutdown" | |
29 | and "platform" modes (see: Documents/power/basic-pm-debugging.txt, 1). | |
30 | ||
31 | c) Compile the driver directly into the kernel and try the STD in the test mode. | |
32 | ||
33 | d) Attempt to suspend to disk with the driver compiled directly into the kernel | |
34 | in the "reboot", "shutdown" and "platform" modes. | |
35 | ||
36 | e) Attempt to suspend to RAM using the s2ram tool with the driver loaded (see: | |
37 | Documents/power/basic-pm-debugging.txt, 2). As far as the STR tests are | |
38 | concerned, it should not matter whether or not the driver is built as a module. | |
39 | ||
40 | Each of the above tests should be repeated several times and the STD tests | |
41 | should be mixed with the STR tests. If any of them fails, the driver cannot be | |
42 | regarded as suspend/resume-safe. |