kernel/linux.git/drivers/base/power, branch v5.4.113

PM: runtime: Fix ordering in pm_runtime_get_suppliers()

2021-04-07T12:47:42+00:00

commit c0c33442f7203704aef345647e14c2fb86071001 upstream. rpm_active indicates how many times the supplier usage_count has been incremented. Consequently it must be updated after pm_runtime_get_sync() of the supplier, not before. Fixes: 4c06c4e6cf63 ("driver core: Fix possible supplier PM-usage counter imbalance") Signed-off-by: Adrian Hunter Cc: 5.1+ # 5.1+ Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

PM: runtime: Fix race getting/putting suppliers at probe

2021-04-07T12:47:42+00:00

commit 9dfacc54a8661bc8be6e08cffee59596ec59f263 upstream. pm_runtime_put_suppliers() must not decrement rpm_active unless the consumer is suspended. That is because, otherwise, it could suspend suppliers for an active consumer. That can happen as follows: static int driver_probe_device(struct device_driver *drv, struct device *dev) { int ret = 0; if (!device_is_registered(dev)) return -ENODEV; dev->can_match = true; pr_debug("bus: '%s': %s: matched device %s with driver %s\n", drv->bus->name, __func__, dev_name(dev), drv->name); pm_runtime_get_suppliers(dev); if (dev->parent) pm_runtime_get_sync(dev->parent); At this point, dev can runtime suspend so rpm_put_suppliers() can run, rpm_active becomes 1 (the lowest value). pm_runtime_barrier(dev); if (initcall_debug) ret = really_probe_debug(dev, drv); else ret = really_probe(dev, drv); Probe callback can have runtime resumed dev, and then runtime put so dev is awaiting autosuspend, but rpm_active is 2. pm_request_idle(dev); if (dev->parent) pm_runtime_put(dev->parent); pm_runtime_put_suppliers(dev); Now pm_runtime_put_suppliers() will put the supplier i.e. rpm_active 2 -> 1, but consumer can still be active. return ret; } Fix by checking the runtime status. For any status other than RPM_SUSPENDED, rpm_active can be considered to be "owned" by rpm_[get/put]_suppliers() and pm_runtime_put_suppliers() need do nothing. Reported-by: Asutosh Das Fixes: 4c06c4e6cf63 ("driver core: Fix possible supplier PM-usage counter imbalance") Signed-off-by: Adrian Hunter Cc: 5.1+ # 5.1+ Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

PM: runtime: Defer suspending suppliers

2021-03-30T12:35:27+00:00

[ Upstream commit 5244f5e2d801259af877ee759e8c22364c607072 ] Because the PM-runtime status of the device is not updated in __rpm_callback(), attempts to suspend the suppliers of the given device triggered by the rpm_put_suppliers() call in there may cause a supplier to be suspended completely before the status of the consumer is updated to RPM_SUSPENDED, which is confusing. To avoid that (1) modify __rpm_callback() to only decrease the PM-runtime usage counter of each supplier and (2) make rpm_suspend() try to suspend the suppliers after changing the consumer's status to RPM_SUSPENDED, in analogy with the device's parent. Link: https://lore.kernel.org/linux-pm/CAPDyKFqm06KDw_p8WXsM4dijDbho4bb6T4k50UqqvR1_COsp8g@mail.gmail.com/ Fixes: 21d5c57b3726 ("PM / runtime: Use device links") Reported-by: elaine.zhang Diagnosed-by: Ulf Hansson Reviewed-by: Ulf Hansson Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin

Revert "PM: runtime: Update device status before letting suppliers suspend"

2021-03-24T10:26:35+00:00

commit 0cab893f409c53634d0d818fa414641cbcdb0dab upstream. Revert commit 44cc89f76464 ("PM: runtime: Update device status before letting suppliers suspend") that introduced a race condition into __rpm_callback() which allowed a concurrent rpm_resume() to run and resume the device prematurely after its status had been changed to RPM_SUSPENDED by __rpm_callback(). Fixes: 44cc89f76464 ("PM: runtime: Update device status before letting suppliers suspend") Link: https://lore.kernel.org/linux-pm/24dfb6fc-5d54-6ee2-9195-26428b7ecf8a@intel.com/ Reported-by: Adrian Hunter Cc: 4.10+ # 4.10+ Signed-off-by: Rafael J. Wysocki Reviewed-by: Ulf Hansson Signed-off-by: Greg Kroah-Hartman

PM: runtime: Update device status before letting suppliers suspend

2021-03-09T10:09:37+00:00

commit 44cc89f764646b2f1f2ea5d1a08b230131707851 upstream. Because the PM-runtime status of the device is not updated in __rpm_callback(), attempts to suspend the suppliers of the given device triggered by rpm_put_suppliers() called by it may fail. Fix this by making __rpm_callback() update the device's status to RPM_SUSPENDED before calling rpm_put_suppliers() if the current status of the device is RPM_SUSPENDING and the callback just invoked by it has returned 0 (success). While at it, modify the code in __rpm_callback() to always check the device's PM-runtime status under its PM lock. Link: https://lore.kernel.org/linux-pm/CAPDyKFqm06KDw_p8WXsM4dijDbho4bb6T4k50UqqvR1_COsp8g@mail.gmail.com/ Fixes: 21d5c57b3726 ("PM / runtime: Use device links") Reported-by: Elaine Zhang Diagnosed-by: Ulf Hansson Signed-off-by: Rafael J. Wysocki Tested-by: Elaine Zhang Reviewed-by: Ulf Hansson Cc: 4.10+ # 4.10+ Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman

PM: runtime: Drop pm_runtime_clean_up_links()

2020-11-10T11:37:34+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

2020-11-10T11:37:34+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()

2020-11-05T10:43:26+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

2020-09-03T09:27:05+00:00

commit e3eb6e8fba65094328b8dca635d00de74ba75b45 upstream. 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 Signed-off-by: Greg Kroah-Hartman

PM: wakeup: Show statistics for deleted wakeup sources again

2020-07-31T16:39:32+00:00

commit e976eb4b91e906f20ec25b20c152d53c472fc3fd upstream. After commit 00ee22c28915 (PM / wakeup: Use seq_open() to show wakeup stats), print_wakeup_source_stats(m, &deleted_ws) is not called from wakeup_sources_stats_seq_show() any more. Because deleted_ws is one of the wakeup sources, it should be shown too, so add it to the end of all other wakeup sources. Signed-off-by: zhuguangqing [ rjw: Subject & changelog ] Signed-off-by: Rafael J. Wysocki Signed-off-by: Florian Fainelli Signed-off-by: Greg Kroah-Hartman