1Testing suspend and resume support in device drivers
   2        (C) 2007 Rafael J. Wysocki <>, GPL
   41. Preparing the test system
   6Unfortunately, to effectively test the support for the system-wide suspend and
   7resume transitions in a driver, it is necessary to suspend and resume a fully
   8functional system with this driver loaded.  Moreover, that should be done
   9several 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
  11cases involves slightly different operations and different interactions with
  12the machine's BIOS.
  14Of course, for this purpose the test system has to be known to suspend and
  15resume without the driver being tested.  Thus, if possible, you should first
  16resolve all suspend/resume-related problems in the test system before you start
  17testing the new driver.  Please see Documentation/power/basic-pm-debugging.txt
  18for more information about the debugging of suspend/resume functionality.
  202. Testing the driver
  22Once you have resolved the suspend/resume-related problems with your test system
  23without the new driver, you are ready to test it:
  25a) Build the driver as a module, load it and try the test modes of hibernation
  26   (see: Documentation/power/basic-pm-debugging.txt, 1).
  28b) Load the driver and attempt to hibernate in the "reboot", "shutdown" and
  29   "platform" modes (see: Documentation/power/basic-pm-debugging.txt, 1).
  31c) Compile the driver directly into the kernel and try the test modes of
  32   hibernation.
  34d) Attempt to hibernate with the driver compiled directly into the kernel
  35   in the "reboot", "shutdown" and "platform" modes.
  37e) 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.]
  41f) Attempt to suspend to RAM using the s2ram tool with the driver loaded
  42   (see: Documentation/power/basic-pm-debugging.txt, 2).
  44Each of the above tests should be repeated several times and the STD tests
  45should be mixed with the STR tests.  If any of them fails, the driver cannot be
  46regarded as suspend/resume-safe.