Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [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 hibernation |
| 10 | (aka suspend to disk or STD) and suspend to RAM (STR), because each of these |
| 11 | cases involves slightly different 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 Documentation/power/basic-pm-debugging.txt |
| 18 | for 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 test modes of hibernation |
| 26 | (see: Documentation/power/basic-pm-debugging.txt, 1). |
| 27 | |
| 28 | b) Load the driver and attempt to hibernate in the "reboot", "shutdown" and |
| 29 | "platform" modes (see: Documentation/power/basic-pm-debugging.txt, 1). |
| 30 | |
| 31 | c) Compile the driver directly into the kernel and try the test modes of |
| 32 | hibernation. |
| 33 | |
| 34 | d) Attempt to hibernate with the driver compiled directly into the kernel |
| 35 | in the "reboot", "shutdown" and "platform" modes. |
| 36 | |
| 37 | e) Try the test modes of suspend (see: Documentation/power/basic-pm-debugging.txt, |
| 38 | 2). [As far as the STR tests are concerned, it should not matter whether or |
| 39 | not the driver is built as a module.] |
| 40 | |
| 41 | f) Attempt to suspend to RAM using the s2ram tool with the driver loaded |
| 42 | (see: Documentation/power/basic-pm-debugging.txt, 2). |
| 43 | |
| 44 | Each of the above tests should be repeated several times and the STD tests |
| 45 | should be mixed with the STR tests. If any of them fails, the driver cannot be |
| 46 | regarded as suspend/resume-safe. |