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-rw-r--r--Documentation/power/devices.txt90
1 files changed, 0 insertions, 90 deletions
diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt
index f987afe43e28..fba1e05c47c7 100644
--- a/Documentation/power/devices.txt
+++ b/Documentation/power/devices.txt
@@ -135,96 +135,6 @@ HW.
135 135
136FREEZE -- stop DMA and interrupts, and be prepared to reinit HW from 136FREEZE -- stop DMA and interrupts, and be prepared to reinit HW from
137scratch. That probably means stop accepting upstream requests, the 137scratch. That probably means stop accepting upstream requests, the
138actual policy of what to do with them beeing specific to a given
139driver. It's acceptable for a network driver to just drop packets
140while a block driver is expected to block the queue so no request is
141lost. (Use IDE as an example on how to do that). FREEZE requires no
142power state change, and it's expected for drivers to be able to
143quickly transition back to operating state.
144
145SUSPEND -- like FREEZE, but also put hardware into low-power state. If
146there's need to distinguish several levels of sleep, additional flag
147is probably best way to do that.
148
149Transitions are only from a resumed state to a suspended state, never
150between 2 suspended states. (ON -> FREEZE or ON -> SUSPEND can happen,
151FREEZE -> SUSPEND or SUSPEND -> FREEZE can not).
152
153All events are:
154
155[NOTE NOTE NOTE: If you are driver author, you should not care; you
156should only look at event, and ignore flags.]
157
158#Prepare for suspend -- userland is still running but we are going to
159#enter suspend state. This gives drivers chance to load firmware from
160#disk and store it in memory, or do other activities taht require
161#operating userland, ability to kmalloc GFP_KERNEL, etc... All of these
162#are forbiden once the suspend dance is started.. event = ON, flags =
163#PREPARE_TO_SUSPEND
164
165Apm standby -- prepare for APM event. Quiesce devices to make life
166easier for APM BIOS. event = FREEZE, flags = APM_STANDBY
167
168Apm suspend -- same as APM_STANDBY, but it we should probably avoid
169spinning down disks. event = FREEZE, flags = APM_SUSPEND
170
171System halt, reboot -- quiesce devices to make life easier for BIOS. event
172= FREEZE, flags = SYSTEM_HALT or SYSTEM_REBOOT
173
174System shutdown -- at least disks need to be spun down, or data may be
175lost. Quiesce devices, just to make life easier for BIOS. event =
176FREEZE, flags = SYSTEM_SHUTDOWN
177
178Kexec -- turn off DMAs and put hardware into some state where new
179kernel can take over. event = FREEZE, flags = KEXEC
180
181Powerdown at end of swsusp -- very similar to SYSTEM_SHUTDOWN, except wake
182may need to be enabled on some devices. This actually has at least 3
183subtypes, system can reboot, enter S4 and enter S5 at the end of
184swsusp. event = FREEZE, flags = SWSUSP and one of SYSTEM_REBOOT,
185SYSTEM_SHUTDOWN, SYSTEM_S4
186
187Suspend to ram -- put devices into low power state. event = SUSPEND,
188flags = SUSPEND_TO_RAM
189
190Freeze for swsusp snapshot -- stop DMA and interrupts. No need to put
191devices into low power mode, but you must be able to reinitialize
192device from scratch in resume method. This has two flavors, its done
193once on suspending kernel, once on resuming kernel. event = FREEZE,
194flags = DURING_SUSPEND or DURING_RESUME
195
196Device detach requested from /sys -- deinitialize device; proably same as
197SYSTEM_SHUTDOWN, I do not understand this one too much. probably event
198= FREEZE, flags = DEV_DETACH.
199
200#These are not really events sent:
201#
202#System fully on -- device is working normally; this is probably never
203#passed to suspend() method... event = ON, flags = 0
204#
205#Ready after resume -- userland is now running, again. Time to free any
206#memory you ate during prepare to suspend... event = ON, flags =
207#READY_AFTER_RESUME
208#
209
210
211pm_message_t meaning
212
213pm_message_t has two fields. event ("major"), and flags. If driver
214does not know event code, it aborts the request, returning error. Some
215drivers may need to deal with special cases based on the actual type
216of suspend operation being done at the system level. This is why
217there are flags.
218
219Event codes are:
220
221ON -- no need to do anything except special cases like broken
222HW.
223
224# NOTIFICATION -- pretty much same as ON?
225
226FREEZE -- stop DMA and interrupts, and be prepared to reinit HW from
227scratch. That probably means stop accepting upstream requests, the
228actual policy of what to do with them being specific to a given 138actual policy of what to do with them being specific to a given
229driver. It's acceptable for a network driver to just drop packets 139driver. It's acceptable for a network driver to just drop packets
230while a block driver is expected to block the queue so no request is 140while a block driver is expected to block the queue so no request is