| Rafael J. Wysocki | 5b79520 | 2007-05-08 00:24:07 -0700 | [diff] [blame] | 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. |