[net-next-2.6.git] / Documentation / power / drivers-testing.txt

Testing suspend and resume support in device drivers
	(C) 2007 Rafael J. Wysocki <rjw@sisk.pl>, GPL

1. Preparing the test system

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 hibernation
(aka suspend to disk or STD) and suspend to RAM (STR), because each of these
cases involves slightly different operations and different interactions with
the machine's BIOS.

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 Documentation/power/basic-pm-debugging.txt
for more information about the debugging of suspend/resume functionality.

2. Testing the driver

Once you have resolved the suspend/resume-related problems with your test system
without the new driver, you are ready to test it:

a) Build the driver as a module, load it and try the test modes of hibernation
   (see: Documents/power/basic-pm-debugging.txt, 1).

b) Load the driver and attempt to hibernate in the "reboot", "shutdown" and
   "platform" modes (see: Documents/power/basic-pm-debugging.txt, 1).

c) Compile the driver directly into the kernel and try the test modes of
   hibernation.

d) Attempt to hibernate with the driver compiled directly into the kernel
   in the "reboot", "shutdown" and "platform" modes.

e) Try the test modes of suspend (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.]

f) Attempt to suspend to RAM using the s2ram tool with the driver loaded
   (see: Documents/power/basic-pm-debugging.txt, 2).

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.
Commit	Line	Data
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
ce2b7147 RW	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
5b795202 RW	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
5e3c3ac9 RB	17	testing the new driver. Please see Documentation/power/basic-pm-debugging.txt
5e3c3ac9 RB	18	for more information about the debugging of suspend/resume functionality.
5b795202 RW	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
ce2b7147 RW	25	a) Build the driver as a module, load it and try the test modes of hibernation
ce2b7147 RW	26	(see: Documents/power/basic-pm-debugging.txt, 1).
5b795202	27
ce2b7147 RW	28	b) Load the driver and attempt to hibernate in the "reboot", "shutdown" and
ce2b7147 RW	29	"platform" modes (see: Documents/power/basic-pm-debugging.txt, 1).
5b795202	30
ce2b7147 RW	31	c) Compile the driver directly into the kernel and try the test modes of
ce2b7147 RW	32	hibernation.
5b795202	33
ce2b7147 RW	34	d) Attempt to hibernate with the driver compiled directly into the kernel
ce2b7147 RW	35	in the "reboot", "shutdown" and "platform" modes.
5b795202	36
ce2b7147 RW	37	e) Try the test modes of suspend (see: Documents/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: Documents/power/basic-pm-debugging.txt, 2).
5b795202 RW	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.