From f99508074e78fea17f06d753d9ef453b174ec98e Mon Sep 17 00:00:00 2001 From: Claudiu Beznea Date: Thu, 3 Jul 2025 14:27:07 +0300 Subject: [PATCH] PM: domains: Detach on device_unbind_cleanup() The dev_pm_domain_attach() function is typically used in bus code alongside dev_pm_domain_detach(), often following patterns like: static int bus_probe(struct device *_dev) { struct bus_driver *drv = to_bus_driver(dev->driver); struct bus_device *dev = to_bus_device(_dev); int ret; // ... ret = dev_pm_domain_attach(_dev, true); if (ret) return ret; if (drv->probe) ret = drv->probe(dev); // ... } static void bus_remove(struct device *_dev) { struct bus_driver *drv = to_bus_driver(dev->driver); struct bus_device *dev = to_bus_device(_dev); if (drv->remove) drv->remove(dev); dev_pm_domain_detach(_dev); } When the driver's probe function uses devres-managed resources that depend on the power domain state, those resources are released later during device_unbind_cleanup(). Releasing devres-managed resources that depend on the power domain state after detaching the device from its PM domain can cause failures. For example, if the driver uses devm_pm_runtime_enable() in its probe function, and the device's clocks are managed by the PM domain, then during removal the runtime PM is disabled in device_unbind_cleanup() after the clocks have been removed from the PM domain. It may happen that the devm_pm_runtime_enable() action causes the device to be runtime- resumed. If the driver specific runtime PM APIs access registers directly, this will lead to accessing device registers without clocks being enabled. Similar issues may occur with other devres actions that access device registers. Add detach_power_off member to struct dev_pm_info, to be used later in device_unbind_cleanup() as the power_off argument for dev_pm_domain_detach(). This is a preparatory step toward removing dev_pm_domain_detach() calls from bus remove functions. Since the current PM domain detach functions (genpd_dev_pm_detach() and acpi_dev_pm_detach()) already set dev->pm_domain = NULL, there should be no issues with bus drivers that still call dev_pm_domain_detach() in their remove functions. Signed-off-by: Claudiu Beznea Reviewed-by: Ulf Hansson Link: https://patch.msgid.link/20250703112708.1621607-3-claudiu.beznea.uj@bp.renesas.com Signed-off-by: Rafael J. Wysocki --- drivers/base/dd.c | 2 ++ drivers/base/power/common.c | 3 +++ include/linux/pm.h | 1 + 3 files changed, 6 insertions(+) diff --git a/drivers/base/dd.c b/drivers/base/dd.c index b526e0e0f52d7..13ab98e033eaa 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include #include @@ -552,6 +553,7 @@ static void device_unbind_cleanup(struct device *dev) dev->dma_range_map = NULL; device_set_driver(dev, NULL); dev_set_drvdata(dev, NULL); + dev_pm_domain_detach(dev, dev->power.detach_power_off); if (dev->pm_domain && dev->pm_domain->dismiss) dev->pm_domain->dismiss(dev); pm_runtime_reinit(dev); diff --git a/drivers/base/power/common.c b/drivers/base/power/common.c index fecb85fa85ac8..6ecf9ce4a4e62 100644 --- a/drivers/base/power/common.c +++ b/drivers/base/power/common.c @@ -111,6 +111,9 @@ int dev_pm_domain_attach(struct device *dev, u32 flags) if (!ret) ret = genpd_dev_pm_attach(dev); + if (dev->pm_domain) + dev->power.detach_power_off = !!(flags & PD_FLAG_DETACH_POWER_OFF); + return ret < 0 ? ret : 0; } EXPORT_SYMBOL_GPL(dev_pm_domain_attach); diff --git a/include/linux/pm.h b/include/linux/pm.h index 938b1b446a5d1..14e8370887e33 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -721,6 +721,7 @@ struct dev_pm_info { struct pm_subsys_data *subsys_data; /* Owned by the subsystem. */ void (*set_latency_tolerance)(struct device *, s32); struct dev_pm_qos *qos; + bool detach_power_off:1; /* Owned by the driver core */ }; extern int dev_pm_get_subsys_data(struct device *dev); -- 2.47.2