| Message ID | 2261308.G18gbxz5ee@kreacher (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
| Series | PM: ACPI: PCI: Address issues related to signaling wakeup from bridges | expand |
On Tue, Nov 24, 2020 at 08:44:00PM +0100, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > The idea behind acpi_pm_set_bridge_wakeup() was to allow bridges to > be reference counted for wakeup enabling, because they may be enabled > to signal wakeup on behalf of their subordinate devices and that > may happen for multiple times in a row, whereas for the other devices > it only makes sense to enable wakeup signaling once. > > However, this becomes problematic if the bridge itself is suspended, > because it is treated as a "regular" device in that case and the > reference counting doesn't work. > > For instance, suppose that there are two devices below a bridge and > they both can signal wakeup. Every time one of them is suspended, > wakeup signaling is enabled for the bridge, so when they both have > been suspended, the bridge's wakeup reference counter value is 2. > > Say that the bridge is suspended subsequently and acpi_pci_wakeup() > is called for it. Because the bridge can signal wakeup, that > function will invoke acpi_pm_set_device_wakeup() to configure it > and __acpi_pm_set_device_wakeup() will be called with the last > argument equal to 1. This causes __acpi_device_wakeup_enable() > invoked by it to omit the reference counting, because the reference > counter of the target device (the bridge) is 2 at that time. > > Now say that the bridge resumes and one of the device below it > resumes too, so the bridge's reference counter becomes 0 and > wakeup signaling is disabled for it, but there is still the other > suspended device which may need the bridge to signal wakeup on its > behalf and that is not going to work. > > To address this scenario, use wakeup enable reference counting for > all devices, not just for bridges, so drop the last argument from > __acpi_device_wakeup_enable() and __acpi_pm_set_device_wakeup(), > which causes acpi_pm_set_device_wakeup() and > acpi_pm_set_bridge_wakeup() to become identical, so drop the latter > and use the former instead of it everywhere. > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
On Tue, Nov 24, 2020 at 08:44:00PM +0100, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > The idea behind acpi_pm_set_bridge_wakeup() was to allow bridges to > be reference counted for wakeup enabling, because they may be enabled > to signal wakeup on behalf of their subordinate devices and that > may happen for multiple times in a row, whereas for the other devices > it only makes sense to enable wakeup signaling once. > > However, this becomes problematic if the bridge itself is suspended, > because it is treated as a "regular" device in that case and the > reference counting doesn't work. > > For instance, suppose that there are two devices below a bridge and > they both can signal wakeup. Every time one of them is suspended, > wakeup signaling is enabled for the bridge, so when they both have > been suspended, the bridge's wakeup reference counter value is 2. > > Say that the bridge is suspended subsequently and acpi_pci_wakeup() > is called for it. Because the bridge can signal wakeup, that > function will invoke acpi_pm_set_device_wakeup() to configure it > and __acpi_pm_set_device_wakeup() will be called with the last > argument equal to 1. This causes __acpi_device_wakeup_enable() > invoked by it to omit the reference counting, because the reference > counter of the target device (the bridge) is 2 at that time. > > Now say that the bridge resumes and one of the device below it > resumes too, so the bridge's reference counter becomes 0 and > wakeup signaling is disabled for it, but there is still the other > suspended device which may need the bridge to signal wakeup on its > behalf and that is not going to work. > > To address this scenario, use wakeup enable reference counting for > all devices, not just for bridges, so drop the last argument from > __acpi_device_wakeup_enable() and __acpi_pm_set_device_wakeup(), > which causes acpi_pm_set_device_wakeup() and > acpi_pm_set_bridge_wakeup() to become identical, so drop the latter > and use the former instead of it everywhere. > > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> > --- > drivers/acpi/device_pm.c | 41 ++++++++++++----------------------------- > drivers/pci/pci-acpi.c | 4 ++-- > include/acpi/acpi_bus.h | 5 ----- > 3 files changed, 14 insertions(+), 36 deletions(-) > > Index: linux-pm/include/acpi/acpi_bus.h > =================================================================== > --- linux-pm.orig/include/acpi/acpi_bus.h > +++ linux-pm/include/acpi/acpi_bus.h > @@ -620,7 +620,6 @@ acpi_status acpi_remove_pm_notifier(stru > bool acpi_pm_device_can_wakeup(struct device *dev); > int acpi_pm_device_sleep_state(struct device *, int *, int); > int acpi_pm_set_device_wakeup(struct device *dev, bool enable); > -int acpi_pm_set_bridge_wakeup(struct device *dev, bool enable); > #else > static inline void acpi_pm_wakeup_event(struct device *dev) > { > @@ -651,10 +650,6 @@ static inline int acpi_pm_set_device_wak > { > return -ENODEV; > } > -static inline int acpi_pm_set_bridge_wakeup(struct device *dev, bool enable) > -{ > - return -ENODEV; > -} > #endif > > #ifdef CONFIG_ACPI_SYSTEM_POWER_STATES_SUPPORT > Index: linux-pm/drivers/acpi/device_pm.c > =================================================================== > --- linux-pm.orig/drivers/acpi/device_pm.c > +++ linux-pm/drivers/acpi/device_pm.c > @@ -749,7 +749,7 @@ static void acpi_pm_notify_work_func(str > static DEFINE_MUTEX(acpi_wakeup_lock); > > static int __acpi_device_wakeup_enable(struct acpi_device *adev, > - u32 target_state, int max_count) > + u32 target_state) > { > struct acpi_device_wakeup *wakeup = &adev->wakeup; > acpi_status status; > @@ -757,9 +757,10 @@ static int __acpi_device_wakeup_enable(s > > mutex_lock(&acpi_wakeup_lock); > > - if (wakeup->enable_count >= max_count) > + if (wakeup->enable_count >= INT_MAX) { > + acpi_handle_info(adev->handle, "Wakeup enable count out of bounds!\n"); > goto out; > - > + } > if (wakeup->enable_count > 0) > goto inc; > > @@ -799,7 +800,7 @@ out: > */ > static int acpi_device_wakeup_enable(struct acpi_device *adev, u32 target_state) > { > - return __acpi_device_wakeup_enable(adev, target_state, 1); > + return __acpi_device_wakeup_enable(adev, target_state); > } > > /** > @@ -829,8 +830,12 @@ out: > mutex_unlock(&acpi_wakeup_lock); > } > > -static int __acpi_pm_set_device_wakeup(struct device *dev, bool enable, > - int max_count) > +/** > + * acpi_pm_set_device_wakeup - Enable/disable remote wakeup for given device. > + * @dev: Device to enable/disable to generate wakeup events. > + * @enable: Whether to enable or disable the wakeup functionality. > + */ > +int acpi_pm_set_device_wakeup(struct device *dev, bool enable) > { > struct acpi_device *adev; > int error; > @@ -850,37 +855,15 @@ static int __acpi_pm_set_device_wakeup(s > return 0; > } > > - error = __acpi_device_wakeup_enable(adev, acpi_target_system_state(), > - max_count); > + error = __acpi_device_wakeup_enable(adev, acpi_target_system_state()); > if (!error) > dev_dbg(dev, "Wakeup enabled by ACPI\n"); > > return error; > } > - > -/** > - * acpi_pm_set_device_wakeup - Enable/disable remote wakeup for given device. > - * @dev: Device to enable/disable to generate wakeup events. > - * @enable: Whether to enable or disable the wakeup functionality. > - */ > -int acpi_pm_set_device_wakeup(struct device *dev, bool enable) > -{ > - return __acpi_pm_set_device_wakeup(dev, enable, 1); > -} > EXPORT_SYMBOL_GPL(acpi_pm_set_device_wakeup); > > /** > - * acpi_pm_set_bridge_wakeup - Enable/disable remote wakeup for given bridge. > - * @dev: Bridge device to enable/disable to generate wakeup events. > - * @enable: Whether to enable or disable the wakeup functionality. > - */ > -int acpi_pm_set_bridge_wakeup(struct device *dev, bool enable) > -{ > - return __acpi_pm_set_device_wakeup(dev, enable, INT_MAX); > -} > -EXPORT_SYMBOL_GPL(acpi_pm_set_bridge_wakeup); > - > -/** > * acpi_dev_pm_low_power - Put ACPI device into a low-power state. > * @dev: Device to put into a low-power state. > * @adev: ACPI device node corresponding to @dev. > Index: linux-pm/drivers/pci/pci-acpi.c > =================================================================== > --- linux-pm.orig/drivers/pci/pci-acpi.c > +++ linux-pm/drivers/pci/pci-acpi.c > @@ -1060,7 +1060,7 @@ static int acpi_pci_propagate_wakeup(str > { > while (bus->parent) { > if (acpi_pm_device_can_wakeup(&bus->self->dev)) > - return acpi_pm_set_bridge_wakeup(&bus->self->dev, enable); > + return acpi_pm_set_device_wakeup(&bus->self->dev, enable); > > bus = bus->parent; > } > @@ -1068,7 +1068,7 @@ static int acpi_pci_propagate_wakeup(str > /* We have reached the root bus. */ > if (bus->bridge) { > if (acpi_pm_device_can_wakeup(bus->bridge)) > - return acpi_pm_set_bridge_wakeup(bus->bridge, enable); > + return acpi_pm_set_device_wakeup(bus->bridge, enable); > } > return 0; > } > > >
Index: linux-pm/include/acpi/acpi_bus.h =================================================================== --- linux-pm.orig/include/acpi/acpi_bus.h +++ linux-pm/include/acpi/acpi_bus.h @@ -620,7 +620,6 @@ acpi_status acpi_remove_pm_notifier(stru bool acpi_pm_device_can_wakeup(struct device *dev); int acpi_pm_device_sleep_state(struct device *, int *, int); int acpi_pm_set_device_wakeup(struct device *dev, bool enable); -int acpi_pm_set_bridge_wakeup(struct device *dev, bool enable); #else static inline void acpi_pm_wakeup_event(struct device *dev) { @@ -651,10 +650,6 @@ static inline int acpi_pm_set_device_wak { return -ENODEV; } -static inline int acpi_pm_set_bridge_wakeup(struct device *dev, bool enable) -{ - return -ENODEV; -} #endif #ifdef CONFIG_ACPI_SYSTEM_POWER_STATES_SUPPORT Index: linux-pm/drivers/acpi/device_pm.c =================================================================== --- linux-pm.orig/drivers/acpi/device_pm.c +++ linux-pm/drivers/acpi/device_pm.c @@ -749,7 +749,7 @@ static void acpi_pm_notify_work_func(str static DEFINE_MUTEX(acpi_wakeup_lock); static int __acpi_device_wakeup_enable(struct acpi_device *adev, - u32 target_state, int max_count) + u32 target_state) { struct acpi_device_wakeup *wakeup = &adev->wakeup; acpi_status status; @@ -757,9 +757,10 @@ static int __acpi_device_wakeup_enable(s mutex_lock(&acpi_wakeup_lock); - if (wakeup->enable_count >= max_count) + if (wakeup->enable_count >= INT_MAX) { + acpi_handle_info(adev->handle, "Wakeup enable count out of bounds!\n"); goto out; - + } if (wakeup->enable_count > 0) goto inc; @@ -799,7 +800,7 @@ out: */ static int acpi_device_wakeup_enable(struct acpi_device *adev, u32 target_state) { - return __acpi_device_wakeup_enable(adev, target_state, 1); + return __acpi_device_wakeup_enable(adev, target_state); } /** @@ -829,8 +830,12 @@ out: mutex_unlock(&acpi_wakeup_lock); } -static int __acpi_pm_set_device_wakeup(struct device *dev, bool enable, - int max_count) +/** + * acpi_pm_set_device_wakeup - Enable/disable remote wakeup for given device. + * @dev: Device to enable/disable to generate wakeup events. + * @enable: Whether to enable or disable the wakeup functionality. + */ +int acpi_pm_set_device_wakeup(struct device *dev, bool enable) { struct acpi_device *adev; int error; @@ -850,37 +855,15 @@ static int __acpi_pm_set_device_wakeup(s return 0; } - error = __acpi_device_wakeup_enable(adev, acpi_target_system_state(), - max_count); + error = __acpi_device_wakeup_enable(adev, acpi_target_system_state()); if (!error) dev_dbg(dev, "Wakeup enabled by ACPI\n"); return error; } - -/** - * acpi_pm_set_device_wakeup - Enable/disable remote wakeup for given device. - * @dev: Device to enable/disable to generate wakeup events. - * @enable: Whether to enable or disable the wakeup functionality. - */ -int acpi_pm_set_device_wakeup(struct device *dev, bool enable) -{ - return __acpi_pm_set_device_wakeup(dev, enable, 1); -} EXPORT_SYMBOL_GPL(acpi_pm_set_device_wakeup); /** - * acpi_pm_set_bridge_wakeup - Enable/disable remote wakeup for given bridge. - * @dev: Bridge device to enable/disable to generate wakeup events. - * @enable: Whether to enable or disable the wakeup functionality. - */ -int acpi_pm_set_bridge_wakeup(struct device *dev, bool enable) -{ - return __acpi_pm_set_device_wakeup(dev, enable, INT_MAX); -} -EXPORT_SYMBOL_GPL(acpi_pm_set_bridge_wakeup); - -/** * acpi_dev_pm_low_power - Put ACPI device into a low-power state. * @dev: Device to put into a low-power state. * @adev: ACPI device node corresponding to @dev. Index: linux-pm/drivers/pci/pci-acpi.c =================================================================== --- linux-pm.orig/drivers/pci/pci-acpi.c +++ linux-pm/drivers/pci/pci-acpi.c @@ -1060,7 +1060,7 @@ static int acpi_pci_propagate_wakeup(str { while (bus->parent) { if (acpi_pm_device_can_wakeup(&bus->self->dev)) - return acpi_pm_set_bridge_wakeup(&bus->self->dev, enable); + return acpi_pm_set_device_wakeup(&bus->self->dev, enable); bus = bus->parent; } @@ -1068,7 +1068,7 @@ static int acpi_pci_propagate_wakeup(str /* We have reached the root bus. */ if (bus->bridge) { if (acpi_pm_device_can_wakeup(bus->bridge)) - return acpi_pm_set_bridge_wakeup(bus->bridge, enable); + return acpi_pm_set_device_wakeup(bus->bridge, enable); } return 0; }