Documentation/power/basic-pm-debugging.rst

21 modes causes the PM core to skip some platform-related callbacks which on ACPI
24 "platform" mode::
26 	# echo platform > /sys/power/disk
31 Unfortunately, the "platform" mode of hibernation does not work on some systems
41 If neither "platform" nor "shutdown" hibernation mode works, you will need to
45 ----------------------------
53 	- test the freezing of processes
56 	- test the freezing of processes and suspending of devices
58 platform
59 	- test the freezing of processes, suspending of devices and platform
63 	- test the freezing of processes, suspending of devices, platform
67 	- test the freezing of processes, suspending of devices, platform global
69 	  of platform/system devices
73     the platform global control methods are only available on ACPI systems
74     and are only tested if the hibernation mode is set to "platform"
79 to use the "devices" test mode along with the "platform" mode of hibernation,
83 	# echo platform > /sys/power/disk
88 parameter), resume devices and thaw processes.  If "platform" is written to
91 prepare the platform firmware for hibernation.  Next, it will wait a
92 configurable number of seconds and invoke the platform (eg. ACPI) global
97 contains a space-separated list of all available tests (including "none" that
98 represents the normal functionality) in which the current test level is
101 Generally, as you can see, each test level is more "invasive" than the previous
102 one and the "core" level tests the hardware and drivers as deeply as possible
104 the "platform" test will fail as well and so on.  Thus, as a rule of thumb, you
105 should try the test modes starting from "freezer", through "devices", "platform"
106 and "processors" up to "core" (repeat the test on each level a couple of times
111 dmesg obtained after the failing test).  Failure at this level usually means
120 - if the test fails, unload a half of the drivers currently loaded and repeat
123 - if the test succeeds, load a half of the drivers you have unloaded most
136 If the "platform" test fails, there is a problem with the handling of the
137 platform (eg. ACPI) firmware on your system.  In that case the "platform" mode
147 If the "core" test fails, which means that suspending of the system/platform
149 the problem is most probably hardware-related and serious, so it should be
152 A failure of any of the "platform", "processors" or "core" tests may cause your
158 --------------------------------
162 "reboot", "shutdown" and "platform" modes.  If that does not work, there
168 - if there are n modules loaded and the attempt to suspend and resume fails,
171 - if there are n modules loaded and the attempt to suspend and resume succeeds,
178 ---------------------------------------------
189 immediately without involving the platform firmware in any way.
192 related to bad interactions with the platform firmware.  That is, if the above
194 unreliable, the platform firmware may be responsible for the failures.
204 ---------------------
224 Namely, after writing "freezer", "devices", "platform", "processors", or "core"
230 invocation of the platform firmware in order to put the system into the sleep
248 	# mount -t debugfs none /sys/kernel/debug
261 	  last_failed_errno:	-16
262 				-16