| Testing suspend and resume support in device drivers |
| (C) 2007 Rafael J. Wysocki <rjw@sisk.pl>, GPL |
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| 1. Preparing the test system |
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| Unfortunately, to effectively test the support for the system-wide suspend and |
| resume transitions in a driver, it is necessary to suspend and resume a fully |
| functional system with this driver loaded. Moreover, that should be done |
| several times, preferably several times in a row, and separately for the suspend |
| to disk (STD) and the suspend to RAM (STR) transitions, because each of these |
| cases involves different ordering of operations and different interactions with |
| the machine's BIOS. |
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| Of course, for this purpose the test system has to be known to suspend and |
| resume without the driver being tested. Thus, if possible, you should first |
| resolve all suspend/resume-related problems in the test system before you start |
| testing the new driver. Please see Documents/power/basic-pm-debugging.txt for |
| more information about the debugging of suspend/resume functionality. |
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| 2. Testing the driver |
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| Once you have resolved the suspend/resume-related problems with your test system |
| without the new driver, you are ready to test it: |
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| a) Build the driver as a module, load it and try the STD in the test mode (see: |
| Documents/power/basic-pm-debugging.txt, 1a)). |
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| b) Load the driver and attempt to suspend to disk in the "reboot", "shutdown" |
| and "platform" modes (see: Documents/power/basic-pm-debugging.txt, 1). |
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| c) Compile the driver directly into the kernel and try the STD in the test mode. |
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| d) Attempt to suspend to disk with the driver compiled directly into the kernel |
| in the "reboot", "shutdown" and "platform" modes. |
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| e) Attempt to suspend to RAM using the s2ram tool with the driver loaded (see: |
| Documents/power/basic-pm-debugging.txt, 2). As far as the STR tests are |
| concerned, it should not matter whether or not the driver is built as a module. |
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| Each of the above tests should be repeated several times and the STD tests |
| should be mixed with the STR tests. If any of them fails, the driver cannot be |
| regarded as suspend/resume-safe. |