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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
| commit | 4352b8aee98005853aa63f57d6377282de17a33f (patch) | |
| tree | 27614d7a9ef05c32d089004e104364ce42324837 /Documentation/driver-api/pm/notifiers.rst | |
| download | linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip | |
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni:
"A new driver this cycle, for the AMD AXI I3C controller.
There are also new features such as IBI wakeup support, SETAASA device
discovery and ACPI support for the the DAA methods, meaning we can now
communicate with the SPD devices on DDR5 modules.
New driver:
- AMD AXI I3C master controller
Subsystem:
- I3C Common Command Code (CCC) handling improvements, especially
around GET CCCs
- SETAASA device discovery support
- ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
well as I2C devices on I3C bus
- IBI-based wakeup support
Drivers:
- dw: SETAASA support
- mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
controller support, PIO queue management support for HCI v1.2
- renesas: improve suspend to RAM support, add runtime PM support"
* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
i3c: dw: reduce do_daa time if there's no client
i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
i3c: dw: rename "pclk" to "apb" to match dt-binding
i3c: dw: make struct dw_i3c_cmd smaller
i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
i3c: renesas: Don't register devices when ENTDAA times out
i3c: master: dw-i3c-master: fix OD timing for first broadcast
i3c: mipi-i3c-hci: Advertise IBI wakeup capability
i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
i3c: master: Reject IBI requests from non-IBI-capable devices
i3c: master: Add helper to query bus wakeup requirements
i3c: master: Report wakeup events for IBIs
i3c: master: Support IBI-based wakeup capability
i3c: master: Fix potential UAF in i3c_device_match()
i3c: master: Fix potential UAF in i3c_device_uevent()
i3c: Make dev->desc locking assumptions explicit
i3c: master: Fix use-after-free of master->this
...
Diffstat (limited to 'Documentation/driver-api/pm/notifiers.rst')
| -rw-r--r-- | Documentation/driver-api/pm/notifiers.rst | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/Documentation/driver-api/pm/notifiers.rst b/Documentation/driver-api/pm/notifiers.rst new file mode 100644 index 000000000..186435c43 --- /dev/null +++ b/Documentation/driver-api/pm/notifiers.rst @@ -0,0 +1,74 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. include:: <isonum.txt> + +============================= +Suspend/Hibernation Notifiers +============================= + +:Copyright: |copy| 2016 Intel Corporation + +:Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com> + + +There are some operations that subsystems or drivers may want to carry out +before hibernation/suspend or after restore/resume, but they require the system +to be fully functional, so the drivers' and subsystems' ``->suspend()`` and +``->resume()`` or even ``->prepare()`` and ``->complete()`` callbacks are not +suitable for this purpose. + +For example, device drivers may want to upload firmware to their devices after +resume/restore, but they cannot do it by calling :c:func:`request_firmware()` +from their ``->resume()`` or ``->complete()`` callback routines (user land +processes are frozen at these points). The solution may be to load the firmware +into memory before processes are frozen and upload it from there in the +``->resume()`` routine. A suspend/hibernation notifier may be used for that. + +Subsystems or drivers having such needs can register suspend notifiers that +will be called upon the following events by the PM core: + +``PM_HIBERNATION_PREPARE`` + The system is going to hibernate, tasks will be frozen immediately. This + is different from ``PM_SUSPEND_PREPARE`` below, because in this case + additional work is done between the notifiers and the invocation of PM + callbacks for the "freeze" transition. + +``PM_POST_HIBERNATION`` + The system memory state has been restored from a hibernation image or an + error occurred during hibernation. Device restore callbacks have been + executed and tasks have been thawed. + +``PM_RESTORE_PREPARE`` + The system is going to restore a hibernation image. If all goes well, + the restored image kernel will issue a ``PM_POST_HIBERNATION`` + notification. + +``PM_POST_RESTORE`` + An error occurred during restore from hibernation. Device restore + callbacks have been executed and tasks have been thawed. + +``PM_SUSPEND_PREPARE`` + The system is preparing for suspend. + +``PM_POST_SUSPEND`` + The system has just resumed or an error occurred during suspend. Device + resume callbacks have been executed and tasks have been thawed. + +It is generally assumed that whatever the notifiers do for +``PM_HIBERNATION_PREPARE``, should be undone for ``PM_POST_HIBERNATION``. +Analogously, operations carried out for ``PM_SUSPEND_PREPARE`` should be +reversed for ``PM_POST_SUSPEND``. + +Moreover, if one of the notifiers fails for the ``PM_HIBERNATION_PREPARE`` or +``PM_SUSPEND_PREPARE`` event, the notifiers that have already succeeded for that +event will be called for ``PM_POST_HIBERNATION`` or ``PM_POST_SUSPEND``, +respectively. + +The hibernation and suspend notifiers are called with :c:data:`pm_mutex` held. +They are defined in the usual way, but their last argument is meaningless (it is +always NULL). + +To register and/or unregister a suspend notifier use +:c:func:`register_pm_notifier()` and :c:func:`unregister_pm_notifier()`, +respectively (both defined in :file:`include/linux/suspend.h`). If you don't +need to unregister the notifier, you can also use the :c:func:`pm_notifier()` +macro defined in :file:`include/linux/suspend.h`. |
