linux/drivers/base/power
Rafael J. Wysocki 8873710660 PM: runtime: Fix supplier device management during consumer probe
Because pm_runtime_get_suppliers() bumps up the rpm_active counter
of each device link to a supplier of the given device in addition
to bumping up the supplier's PM-runtime usage counter, a runtime
suspend of the consumer device may case the latter to go down to 0
when pm_runtime_put_suppliers() is running on a remote CPU.  If that
happens after pm_runtime_put_suppliers() has released power.lock for
the consumer device, and a runtime resume of that device takes place
immediately after it, before pm_runtime_put() is called for the
supplier, that pm_runtime_put() call may cause the supplier to be
suspended even though the consumer is active.

To prevent that from happening, modify pm_runtime_get_suppliers() to
call pm_runtime_get_sync() for the given device's suppliers without
touching the rpm_active counters of the involved device links
Accordingly, modify pm_runtime_put_suppliers() to call pm_runtime_put()
for the given device's suppliers without looking at the rpm_active
counters of the device links at hand.  [This is analogous to what
happened before commit 4c06c4e6cf ("driver core: Fix possible
supplier PM-usage counter imbalance").]

Since pm_runtime_get_suppliers() sets supplier_preactivated for each
device link where the supplier's PM-runtime usage counter has been
incremented and pm_runtime_put_suppliers() calls pm_runtime_put() for
the suppliers whose device links have supplier_preactivated set, the
PM-runtime usage counter is balanced for each supplier and this is
independent of the runtime suspend and resume of the consumer device.

However, in case a device link with DL_FLAG_PM_RUNTIME set is dropped
during the consumer device probe, so pm_runtime_get_suppliers() bumps
up the supplier's PM-runtime usage counter, but it cannot be dropped by
pm_runtime_put_suppliers(), make device_link_release_fn() take care of
that.

Fixes: 4c06c4e6cf ("driver core: Fix possible supplier PM-usage counter imbalance")
Reported-by: Peter Wang <peter.wang@mediatek.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Peter Wang <peter.wang@mediatek.com>
Cc: 5.1+ <stable@vger.kernel.org> # 5.1+
2022-07-01 21:04:15 +02:00
..
clock_ops.c PM: runtime: add devm_pm_clk_create helper 2021-08-26 11:28:07 -07:00
common.c PM: domains: Extend dev_pm_domain_detach() doc 2022-04-13 17:07:58 +02:00
domain_governor.c PM: domains: Allocate governor data dynamically based on a genpd governor 2022-05-19 20:16:05 +02:00
domain.c PM: domains: Trust domain-idle-states from DT to be correct by genpd 2022-05-19 20:16:05 +02:00
generic_ops.c drivers: base: power: add proper SPDX identifiers on files that did not have them. 2019-04-04 20:03:40 +02:00
main.c Merge branches 'pm-sleep', 'pm-domains' and 'pm-docs' 2022-03-18 18:29:21 +01:00
Makefile PM / QoS: Initial kunit test 2019-11-29 12:04:49 +01:00
power.h PM / wakeirq: support enabling wake-up irq after runtime_suspend called 2021-10-27 20:49:32 +02:00
qos-test.c kunit: allow kunit tests to be loaded as a module 2020-01-09 16:42:29 -07:00
qos.c PM / QoS: Restore DEV_PM_QOS_MIN/MAX_FREQUENCY 2019-11-29 12:04:50 +01:00
runtime.c PM: runtime: Fix supplier device management during consumer probe 2022-07-01 21:04:15 +02:00
sysfs.c drivers core: Miscellaneous changes for sysfs_emit 2020-10-02 13:12:07 +02:00
trace.c rtc: Check return value from mc146818_get_time() 2021-12-16 21:50:06 +01:00
wakeirq.c PM: sleep: wakeup: Fix typos in comments 2022-03-01 16:17:32 +01:00
wakeup_stats.c PM: wakeup: remove redundant assignment to variable retval 2021-04-22 15:22:38 +02:00
wakeup.c PM: wakeup: expose pm_wakeup_pending to modules 2022-05-19 19:40:25 +02:00