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authorRafael J. Wysocki <rjw@sisk.pl>2011-06-18 13:53:57 -0400
committerRafael J. Wysocki <rjw@sisk.pl>2011-06-21 17:19:15 -0400
commit78420884e680da8fbc3240de2d3106437042381e (patch)
treee527e3f745a6c69689fbe66c6a85a08cffa0e778 /Documentation/power
parent129b656a0de9a229a72fe4bb6bacd134a1477b44 (diff)
PM: Update documentation regarding sysdevs
The part of Documentation/power/devices.txt regarding sysdevs is not valid any more after commit 2e711c04dbbf7a7732a3f7073b1fc285d12b369d (PM: Remove sysdev suspend, resume and shutdown operations), so remove it. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Diffstat (limited to 'Documentation/power')
-rw-r--r--Documentation/power/devices.txt26
1 files changed, 0 insertions, 26 deletions
diff --git a/Documentation/power/devices.txt b/Documentation/power/devices.txt
index 88880839ece4..ff923fe67d98 100644
--- a/Documentation/power/devices.txt
+++ b/Documentation/power/devices.txt
@@ -549,32 +549,6 @@ callbacks. The other platforms need not implement it or take it into account
549in any way. 549in any way.
550 550
551 551
552System Devices
553--------------
554System devices (sysdevs) follow a slightly different API, which can be found in
555
556 include/linux/sysdev.h
557 drivers/base/sys.c
558
559System devices will be suspended with interrupts disabled, and after all other
560devices have been suspended. On resume, they will be resumed before any other
561devices, and also with interrupts disabled. These things occur in special
562"sysdev_driver" phases, which affect only system devices.
563
564Thus, after the suspend_noirq (or freeze_noirq or poweroff_noirq) phase, when
565the non-boot CPUs are all offline and IRQs are disabled on the remaining online
566CPU, then a sysdev_driver.suspend phase is carried out, and the system enters a
567sleep state (or a system image is created). During resume (or after the image
568has been created or loaded) a sysdev_driver.resume phase is carried out, IRQs
569are enabled on the only online CPU, the non-boot CPUs are enabled, and the
570resume_noirq (or thaw_noirq or restore_noirq) phase begins.
571
572Code to actually enter and exit the system-wide low power state sometimes
573involves hardware details that are only known to the boot firmware, and
574may leave a CPU running software (from SRAM or flash memory) that monitors
575the system and manages its wakeup sequence.
576
577
578Device Low Power (suspend) States 552Device Low Power (suspend) States
579--------------------------------- 553---------------------------------
580Device low-power states aren't standard. One device might only handle 554Device low-power states aren't standard. One device might only handle