From: Rafael J. Wysocki rafael.j.wysocki@intel.com
[ Upstream commit a2d7b2e004af6b09f21ac3d10f8f4456c16a8ddf ]
If an ACPI wakeup power resource is shared between multiple devices, it may not be managed correctly.
Suppose, for example, that two devices, A and B, share a wakeup power resource P whose wakeup_enabled flag is 0 initially. Next, suppose that wakeup power is enabled for A and B, in this order, and disabled for B. When wakeup power is enabled for A, P will be turned on and its wakeup_enabled flag will be set. Next, when wakeup power is enabled for B, P will not be touched, because its wakeup_enabled flag is set. Now, when wakeup power is disabled for B, P will be turned off which is incorrect, because A will still need P in order to signal wakeup.
Moreover, if wakeup power is enabled for A and then disabled for B, the latter will cause P to be turned off incorrectly (it will be still needed by A), because acpi_disable_wakeup_device_power() is allowed to manipulate power resources when the wakeup.prepare_count counter of the given device is 0.
While the first issue could be addressed by changing the wakeup_enabled power resource flag into a counter, addressing the second one requires modifying acpi_disable_wakeup_device_power() to do nothing when the target device's wakeup.prepare_count reference counter is zero and that would cause the new counter to be redundant. Namely, if acpi_disable_wakeup_device_power() is modified as per the above, every change of the new counter following a wakeup.prepare_count change would be reflected by the analogous change of the main reference counter of the given power resource.
Accordingly, modify acpi_disable_wakeup_device_power() to do nothing when the target device's wakeup.prepare_count reference counter is zero and drop the power resource wakeup_enabled flag altogether.
While at it, ensure that all of the power resources that can be turned off will be turned off when disabling device wakeup due to a power resource manipulation error, to prevent energy from being wasted.
Fixes: b5d667eb392e ("ACPI / PM: Take unusual configurations of power resources into account") Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/acpi/power.c | 69 +++++++++++++++----------------------------- 1 file changed, 24 insertions(+), 45 deletions(-)
diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c index 3d34cee0cc101..4b42debeed455 100644 --- a/drivers/acpi/power.c +++ b/drivers/acpi/power.c @@ -52,7 +52,6 @@ struct acpi_power_resource { u32 order; unsigned int ref_count; u8 state; - bool wakeup_enabled; struct mutex resource_lock; struct list_head dependents; }; @@ -710,7 +709,6 @@ int acpi_device_sleep_wake(struct acpi_device *dev, */ int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state) { - struct acpi_power_resource_entry *entry; int err = 0;
if (!dev || !dev->wakeup.flags.valid) @@ -721,26 +719,13 @@ int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state) if (dev->wakeup.prepare_count++) goto out;
- list_for_each_entry(entry, &dev->wakeup.resources, node) { - struct acpi_power_resource *resource = entry->resource; - - mutex_lock(&resource->resource_lock); - - if (!resource->wakeup_enabled) { - err = acpi_power_on_unlocked(resource); - if (!err) - resource->wakeup_enabled = true; - } - - mutex_unlock(&resource->resource_lock); - - if (err) { - dev_err(&dev->dev, - "Cannot turn wakeup power resources on\n"); - dev->wakeup.flags.valid = 0; - goto out; - } + err = acpi_power_on_list(&dev->wakeup.resources); + if (err) { + dev_err(&dev->dev, "Cannot turn on wakeup power resources\n"); + dev->wakeup.flags.valid = 0; + goto out; } + /* * Passing 3 as the third argument below means the device may be * put into arbitrary power state afterward. @@ -770,39 +755,33 @@ int acpi_disable_wakeup_device_power(struct acpi_device *dev)
mutex_lock(&acpi_device_lock);
- if (--dev->wakeup.prepare_count > 0) + if (dev->wakeup.prepare_count > 1) { + dev->wakeup.prepare_count--; goto out; + }
- /* - * Executing the code below even if prepare_count is already zero when - * the function is called may be useful, for example for initialisation. - */ - if (dev->wakeup.prepare_count < 0) - dev->wakeup.prepare_count = 0; + /* Do nothing if wakeup power has not been enabled for this device. */ + if (!dev->wakeup.prepare_count) + goto out;
err = acpi_device_sleep_wake(dev, 0, 0, 0); if (err) goto out;
+ /* + * All of the power resources in the list need to be turned off even if + * there are errors. + */ list_for_each_entry(entry, &dev->wakeup.resources, node) { - struct acpi_power_resource *resource = entry->resource; - - mutex_lock(&resource->resource_lock); - - if (resource->wakeup_enabled) { - err = acpi_power_off_unlocked(resource); - if (!err) - resource->wakeup_enabled = false; - } - - mutex_unlock(&resource->resource_lock); + int ret;
- if (err) { - dev_err(&dev->dev, - "Cannot turn wakeup power resources off\n"); - dev->wakeup.flags.valid = 0; - break; - } + ret = acpi_power_off(entry->resource); + if (ret && !err) + err = ret; + } + if (err) { + dev_err(&dev->dev, "Cannot turn off wakeup power resources\n"); + dev->wakeup.flags.valid = 0; }
out: