kernel/linux.git/drivers/base/power, branch linux-5.9.y

PM: runtime: Drop pm_runtime_clean_up_links()

2020-11-10T11:39:10+00:00

commit d6e36668598154820177bfd78c1621d8e6c580a2 upstream. After commit d12544fb2aa9 ("PM: runtime: Remove link state checks in rpm_get/put_supplier()") nothing prevents the consumer device's runtime PM from acquiring additional references to the supplier device after pm_runtime_clean_up_links() has run (or even while it is running), so calling this function from __device_release_driver() may be pointless (or even harmful). Moreover, it ignores stateless device links, so the runtime PM handling of managed and stateless device links is inconsistent because of it, so better get rid of it entirely. Fixes: d12544fb2aa9 ("PM: runtime: Remove link state checks in rpm_get/put_supplier()") Signed-off-by: Rafael J. Wysocki Cc: 5.1+ # 5.1+ Tested-by: Xiang Chen Reviewed-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

PM: runtime: Drop runtime PM references to supplier on link removal

2020-11-10T11:39:10+00:00

commit e0e398e204634db8fb71bd89cf2f6e3e5bd09b51 upstream. While removing a device link, drop the supplier device's runtime PM usage counter as many times as needed to drop all of the runtime PM references to it from the consumer in addition to dropping the consumer's link count. Fixes: baa8809f6097 ("PM / runtime: Optimize the use of device links") Signed-off-by: Rafael J. Wysocki Cc: 5.1+ # 5.1+ Tested-by: Xiang Chen Reviewed-by: Greg Kroah-Hartman Signed-off-by: Greg Kroah-Hartman

PM: runtime: Remove link state checks in rpm_get/put_supplier()

2020-11-05T10:51:35+00:00

commit d12544fb2aa9944b180c35914031a8384ab082c1 upstream. To support runtime PM for hisi SAS driver (the driver is in directory drivers/scsi/hisi_sas), we add device link between scsi_device->sdev_gendev (consumer device) and hisi_hba->dev(supplier device) with flags DL_FLAG_PM_RUNTIME | DL_FLAG_RPM_ACTIVE. After runtime suspended consumers and supplier, unload the dirver which causes a hung. We found that it called function device_release_driver_internal() to release the supplier device (hisi_hba->dev), as the device link was busy, it set the device link state to DL_STATE_SUPPLIER_UNBIND, and then it called device_release_driver_internal() to release the consumer device (scsi_device->sdev_gendev). Then it would try to call pm_runtime_get_sync() to resume the consumer device, but because consumer-supplier relation existed, it would try to resume the supplier first, but as the link state was already DL_STATE_SUPPLIER_UNBIND, so it skipped resuming the supplier and only resumed the consumer which hanged (it sends IOs to resume scsi_device while the SAS controller is suspended). Simple flow is as follows: device_release_driver_internal -> (supplier device) if device_links_busy -> device_links_unbind_consumers -> ... WRITE_ONCE(link->status, DL_STATE_SUPPLIER_UNBIND) device_release_driver_internal (consumer device) pm_runtime_get_sync -> (consumer device) ... __rpm_callback -> rpm_get_suppliers -> if link->state == DL_STATE_SUPPLIER_UNBIND -> skip the action of resuming the supplier ... pm_runtime_clean_up_links ... Correct suspend/resume ordering between a supplier device and its consumer devices (resume the supplier device before resuming consumer devices, and suspend consumer devices before suspending the supplier device) should be guaranteed by runtime PM, but the state checks in rpm_get_supplier() and rpm_put_supplier() break this rule, so remove them. Signed-off-by: Xiang Chen [ rjw: Subject and changelog edits ] Cc: All applicable Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

PM: sleep: core: Fix the handling of pending runtime resume requests

2020-08-25T14:28:23+00:00

It has been reported that system-wide suspend may be aborted in the absence of any wakeup events due to unforseen interactions of it with the runtume PM framework. One failing scenario is when there are multiple devices sharing an ACPI power resource and runtime-resume needs to be carried out for one of them during system-wide suspend (for example, because it needs to be reconfigured before the whole system goes to sleep). In that case, the runtime-resume of that device involves turning the ACPI power resource "on" which in turn causes runtime-resume requests to be queued up for all of the other devices sharing it. Those requests go to the runtime PM workqueue which is frozen during system-wide suspend, so they are not actually taken care of until the resume of the whole system, but the pm_runtime_barrier() call in __device_suspend() sees them and triggers system wakeup events for them which then cause the system-wide suspend to be aborted if wakeup source objects are in active use. Of course, the logic that leads to triggering those wakeup events is questionable in the first place, because clearly there are cases in which a pending runtime resume request for a device is not connected to any real wakeup events in any way (like the one above). Moreover, it is racy, because the device may be resuming already by the time the pm_runtime_barrier() runs and so if the driver doesn't take care of signaling the wakeup event as appropriate, it will be lost. However, if the driver does take care of that, the extra pm_wakeup_event() call in the core is redundant. Accordingly, drop the conditional pm_wakeup_event() call fron __device_suspend() and make the latter call pm_runtime_barrier() alone. Also modify the comment next to that call to reflect the new code and extend it to mention the need to avoid unwanted interactions between runtime PM and system-wide device suspend callbacks. Fixes: 1e2ef05bb8cf8 ("PM: Limit race conditions between runtime PM and system sleep (v2)") Signed-off-by: Rafael J. Wysocki Acked-by: Alan Stern Reported-by: Utkarsh H Patel Tested-by: Utkarsh H Patel Tested-by: Pengfei Xu Cc: All applicable

PM: runtime: Improve kerneldoc of pm_runtime_get_if_active()

2020-08-04T10:40:10+00:00

The kerneldoc comment of pm_runtime_get_if_active() doesn't list the second argument of the function properly, so fix that and while at it clarify that comment somewhat and add some markup to it. Signed-off-by: Rafael J. Wysocki Reviewed-by: Sakari Ailus

Merge branches 'pm-sleep', 'pm-domains', 'powercap' and 'pm-tools'

2020-08-03T11:12:44+00:00

* pm-sleep: PM: sleep: spread "const char *" correctness PM: hibernate: fix white space in a few places freezer: Add unsafe version of freezable_schedule_timeout_interruptible() for NFS PM: sleep: core: Emit changed uevent on wakeup_sysfs_add/remove * pm-domains: PM: domains: Restore comment indentation for generic_pm_domain.child_links PM: domains: Fix up terminology with parent/child * powercap: powercap: Add Power Limit4 support powercap: idle_inject: Replace play_idle() with play_idle_precise() in comments powercap: intel_rapl: add support for Sapphire Rapids * pm-tools: pm-graph v5.7 - important s2idle fixes cpupower: Replace HTTP links with HTTPS ones cpupower: Fix NULL but dereferenced coccicheck errors cpupower: Fix comparing pointer to 0 coccicheck warns

PM: sleep: core: Emit changed uevent on wakeup_sysfs_add/remove

2020-07-14T17:19:04+00:00

Udev rules that depend on the power/wakeup attribute don't get triggered correctly if device_set_wakeup_capable is called after the device is created. This can happen for several reasons (driver sets wakeup after device is created, wakeup is changed on parent device, etc) and it seems reasonable to emit a changed event when adding or removing attributes on the device. Signed-off-by: Abhishek Pandit-Subedi Reviewed-by: Greg Kroah-Hartman Reviewed-by: Stephen Boyd Signed-off-by: Rafael J. Wysocki

PM: domains: Fix up terminology with parent/child

2020-07-09T12:24:00+00:00

The genpd infrastructure uses the terms master/slave, but such uses have no external exposures (not even in Documentation/driver-api/pm/*) and are not mandated by nor associated with any external specifications. Change the language used through-out to parent/child. There was one possible exception in the debugfs node "pm_genpd/pm_genpd_summary" but its path has no hits outside of the kernel itself when performing a code search[1], and it seems even this single usage has been non-functional since it was introduced due to a typo in the Python ("apend" instead of correct "append"). Fix the typo while we're at it. Link: https://codesearch.debian.net/ # [1] Signed-off-by: Kees Cook Reviewed-by: Greg Kroah-Hartman Reviewed-by: Kieran Bingham Signed-off-by: Rafael J. Wysocki

PM: sleep: core: mark 2 functions as __init to save some memory

2020-06-23T15:35:33+00:00

'early_resume_init()' and 'late_resume_init() 'are only called respectively via 'early_resume_init' and 'late_resume_init'. They can be marked as __init to save a few bytes of memory. Signed-off-by: Christophe JAILLET [ rjw: Subject edits ] Signed-off-by: Rafael J. Wysocki

kernel: rename show_stack_loglvl() => show_stack()

2020-06-09T16:39:13+00:00

Now the last users of show_stack() got converted to use an explicit log level, show_stack_loglvl() can drop it's redundant suffix and become once again well known show_stack(). Signed-off-by: Dmitry Safonov Signed-off-by: Andrew Morton Link: http://lkml.kernel.org/r/20200418201944.482088-51-dima@arista.com Signed-off-by: Linus Torvalds