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-rw-r--r--Documentation/power/devices.txt13
1 files changed, 8 insertions, 5 deletions
diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt
index c53d26361919..461e4f1dbec4 100644
--- a/Documentation/power/devices.txt
+++ b/Documentation/power/devices.txt
@@ -310,9 +310,12 @@ used with suspend-to-disk:
310 PM_EVENT_SUSPEND -- quiesce the driver and put hardware into a low-power 310 PM_EVENT_SUSPEND -- quiesce the driver and put hardware into a low-power
311 state. When used with system sleep states like "suspend-to-RAM" or 311 state. When used with system sleep states like "suspend-to-RAM" or
312 "standby", the upcoming resume() call will often be able to rely on 312 "standby", the upcoming resume() call will often be able to rely on
313 state kept in hardware, or issue system wakeup events. When used 313 state kept in hardware, or issue system wakeup events.
314 instead with suspend-to-disk, few devices support this capability; 314
315 most are completely powered off. 315 PM_EVENT_HIBERNATE -- Put hardware into a low-power state and enable wakeup
316 events as appropriate. It is only used with hibernation
317 (suspend-to-disk) and few devices are able to wake up the system from
318 this state; most are completely powered off.
316 319
317 PM_EVENT_FREEZE -- quiesce the driver, but don't necessarily change into 320 PM_EVENT_FREEZE -- quiesce the driver, but don't necessarily change into
318 any low power mode. A system snapshot is about to be taken, often 321 any low power mode. A system snapshot is about to be taken, often
@@ -329,8 +332,8 @@ used with suspend-to-disk:
329 wakeup events nor DMA are allowed. 332 wakeup events nor DMA are allowed.
330 333
331To enter "standby" (ACPI S1) or "Suspend to RAM" (STR, ACPI S3) states, or 334To enter "standby" (ACPI S1) or "Suspend to RAM" (STR, ACPI S3) states, or
332the similarly named APM states, only PM_EVENT_SUSPEND is used; for "Suspend 335the similarly named APM states, only PM_EVENT_SUSPEND is used; the other event
333to Disk" (STD, hibernate, ACPI S4), all of those event codes are used. 336codes are used for hibernation ("Suspend to Disk", STD, ACPI S4).
334 337
335There's also PM_EVENT_ON, a value which never appears as a suspend event 338There's also PM_EVENT_ON, a value which never appears as a suspend event
336but is sometimes used to record the "not suspended" device state. 339but is sometimes used to record the "not suspended" device state.