linux/drivers/base
Rafael J. Wysocki bca84a7b93 PM: sleep: Use DPM_FLAG_SMART_SUSPEND conditionally
A recent discussion has revealed that using DPM_FLAG_SMART_SUSPEND
unconditionally is generally problematic because it may lead to
situations in which the device's runtime PM information is internally
inconsistent or does not reflect its real state [1].

For this reason, change the handling of DPM_FLAG_SMART_SUSPEND so that
it is only taken into account if it is consistently set by the drivers
of all devices having any PM callbacks throughout dependency graphs in
accordance with the following rules:

 - The "smart suspend" feature is only enabled for devices whose drivers
   ask for it (that is, set DPM_FLAG_SMART_SUSPEND) and for devices
   without PM callbacks unless they have never had runtime PM enabled.

 - The "smart suspend" feature is not enabled for a device if it has not
   been enabled for the device's parent unless the parent does not take
   children into account or it has never had runtime PM enabled.

 - The "smart suspend" feature is not enabled for a device if it has not
   been enabled for one of the device's suppliers taking runtime PM into
   account unless that supplier has never had runtime PM enabled.

Namely, introduce a new device PM flag called smart_suspend that is only
set if the above conditions are met and update all DPM_FLAG_SMART_SUSPEND
users to check power.smart_suspend instead of directly checking the
latter.

At the same time, drop the power.set_active flage introduced recently
in commit 3775fc538f ("PM: sleep: core: Synchronize runtime PM status
of parents and children") because it is now sufficient to check
power.smart_suspend along with the dev_pm_skip_resume() return value
to decide whether or not pm_runtime_set_active() needs to be called
for the device.

Link: https://lore.kernel.org/linux-pm/CAPDyKFroyU3YDSfw_Y6k3giVfajg3NQGwNWeteJWqpW29BojhQ@mail.gmail.com/ [1]
Fixes: 7585946243 ("PM: sleep: core: Restrict power.set_active propagation")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> # drivers/pci
Link: https://patch.msgid.link/1914558.tdWV9SEqCh@rjwysocki.net
2025-02-19 13:22:12 +01:00
..
firmware_loader Summary: 2025-01-29 10:35:40 -08:00
power PM: sleep: Use DPM_FLAG_SMART_SUSPEND conditionally 2025-02-19 13:22:12 +01:00
regmap regmap-irq: Add missing kfree() 2025-02-05 11:55:42 +00:00
test drivers: base: test: Add ...find_device_by...(... NULL) tests 2024-12-24 09:48:09 +01:00
arch_numa.c arch_numa: Restore nid checks before registering a memblock with a node 2024-12-01 22:04:52 +02:00
arch_topology.c ACPI: processor: Move arch_init_invariance_cppc() call later 2024-11-06 21:31:36 +01:00
attribute_container.c driver core: attribute_container: Remove unused functions 2024-09-13 15:41:42 +02:00
auxiliary_sysfs.c driver core: auxiliary bus: show auxiliary device IRQs 2024-07-11 14:17:03 -07:00
auxiliary.c driver core: auxiliary bus: Spelling s/pecific/specific/ 2024-11-04 01:58:10 +01:00
base.h driver core: add a faux bus for use when a simple device/bus is needed 2025-02-13 16:58:51 +01:00
bus.c driver core: Introduce device_iter_t for device iterating APIs 2025-01-10 15:26:12 +01:00
cacheinfo.c cacheinfo: Allocate memory during CPU hotplug if not done from the primary CPU 2024-12-06 13:07:47 +01:00
class.c drivers: core: remove device_link argument from class_compat_[create|remove]_link 2025-01-10 15:42:20 +01:00
component.c driver core: component: fix spellos 2024-01-30 15:58:06 -08:00
container.c driver core: container: make container_subsys const 2023-12-21 13:56:10 +01:00
core.c driver core: Move two simple APIs for finding child device to header 2025-01-10 15:26:12 +01:00
cpu.c riscv: Add ghostwrite vulnerability 2025-01-18 12:33:39 -08:00
dd.c Driver core update for 6.12-rc1 2024-09-27 08:48:37 -07:00
devcoredump.c devcoredump: Constify 'struct bin_attribute' 2025-01-15 18:30:58 +01:00
devres.c devres: add devm_remove_action_nowarn() 2025-01-10 15:49:06 +01:00
devtmpfs.c
driver.c driver core: Introduce device_iter_t for device iterating APIs 2025-01-10 15:26:12 +01:00
faux.c driver core: add a faux bus for use when a simple device/bus is needed 2025-02-13 16:58:51 +01:00
firmware.c
hypervisor.c
init.c driver core: add a faux bus for use when a simple device/bus is needed 2025-02-13 16:58:51 +01:00
isa.c driver core: have match() callback in struct bus_type take a const * 2024-07-03 15:16:54 +02:00
Kconfig arch_numa: switch over to numa_memblks 2024-09-03 21:15:32 -07:00
Makefile driver core: add a faux bus for use when a simple device/bus is needed 2025-02-13 16:58:51 +01:00
map.c
memory.c mm: add build-time option for hotplug memory default online type 2025-01-25 20:22:21 -08:00
module.c Revert "driver core: Fix uevent_show() vs driver detach race" 2024-10-29 01:23:43 +01:00
node.c driver core: Constify bin_attribute definitions 2024-11-15 19:29:16 +01:00
physical_location.c ACPI: bus: change the prototype for acpi_get_physical_device_location 2024-12-19 20:59:35 +01:00
physical_location.h
pinctrl.c
platform-msi.c genirq/msi: Remove platform MSI leftovers 2024-07-18 20:31:21 +02:00
platform.c platform: Make platform_bus_type constant 2024-09-03 13:00:50 +02:00
property.c device property: Split property reading bool and presence test ops 2025-01-13 17:47:29 -06:00
soc.c driver core: mark remaining local bus_type variables as const 2023-12-21 13:56:30 +01:00
swnode.c device property: Split property reading bool and presence test ops 2025-01-13 17:47:29 -06:00
syscore.c
topology.c topology: Keep the cpumask unchanged when printing cpumap 2025-01-07 17:58:08 +01:00
trace.c
trace.h devres: Fix page faults when tracing devres from unloaded modules 2024-10-14 08:21:09 +02:00
transport_class.c