From 8f7412a792bc989d1bddd3c802282eec09456d57 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Fri, 14 Sep 2012 00:26:24 +0200 Subject: [PATCH 1/3] ACPI / PM: Infer parent power state from child if unknown, v2 It turns out that there are ACPI BIOSes defining device objects with _PSx and without either _PSC or _PRx. For devices corresponding to those ACPI objetcs __acpi_bus_get_power() returns ACPI_STATE_UNKNOWN and their initial power states are regarded as unknown as a result. If such a device is a parent of another power-manageable device, the child cannot be put into a low-power state through ACPI, because __acpi_bus_set_power() refuses to change power states of devices whose parents' power states are unknown. To work around this problem, observe that the ACPI power state of a device cannot be higher-power (lower-number) than the power state of its parent. Thus, if the device's _PSC method or the configuration of its power resources indicates that the device is in D0, the device's parent has to be in D0 as well. Consequently, if the parent's power state is unknown when we've just learned that its child's power state is D0, we can safely set the parent's power.state field to ACPI_STATE_D0. Tested-by: Aaron Lu Cc: stable@vger.kernel.org Signed-off-by: Rafael J. Wysocki --- drivers/acpi/bus.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c index 9628652e080c..e0596954290b 100644 --- a/drivers/acpi/bus.c +++ b/drivers/acpi/bus.c @@ -237,6 +237,16 @@ static int __acpi_bus_get_power(struct acpi_device *device, int *state) } else if (result == ACPI_STATE_D3_HOT) { result = ACPI_STATE_D3; } + + /* + * If we were unsure about the device parent's power state up to this + * point, the fact that the device is in D0 implies that the parent has + * to be in D0 too. + */ + if (device->parent && device->parent->power.state == ACPI_STATE_UNKNOWN + && result == ACPI_STATE_D0) + device->parent->power.state = ACPI_STATE_D0; + *state = result; out: From 40bf66ec9791f1452b90b82aadc3b6e6aee201f5 Mon Sep 17 00:00:00 2001 From: Lin Ming Date: Fri, 14 Sep 2012 00:26:33 +0200 Subject: [PATCH 2/3] ACPI / PM: Fix resource_lock dead lock in acpi_power_on_device Commit 0090def("ACPI: Add interface to register/unregister device to/from power resources") used resource_lock to protect the devices list that relies on power resource. It caused a mutex dead lock, as below acpi_power_on ---> lock resource_lock __acpi_power_on acpi_power_on_device acpi_power_get_inferred_state acpi_power_get_list_state ---> lock resource_lock This patch adds a new mutex "devices_lock" to protect the devices list and calls acpi_power_on_device in acpi_power_on, instead of __acpi_power_on, after the resource_lock is released. [rjw: Changed data type of a boolean variable to bool.] Signed-off-by: Lin Ming Signed-off-by: Aaron Lu Cc: stable@vger.kernel.org Signed-off-by: Rafael J. Wysocki --- drivers/acpi/power.c | 34 +++++++++++++++++++++++----------- 1 file changed, 23 insertions(+), 11 deletions(-) diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c index fc1803414629..cc2a2dcff336 100644 --- a/drivers/acpi/power.c +++ b/drivers/acpi/power.c @@ -107,6 +107,7 @@ struct acpi_power_resource { /* List of devices relying on this power resource */ struct acpi_power_resource_device *devices; + struct mutex devices_lock; }; static struct list_head acpi_power_resource_list; @@ -225,7 +226,6 @@ static void acpi_power_on_device(struct acpi_power_managed_device *device) static int __acpi_power_on(struct acpi_power_resource *resource) { - struct acpi_power_resource_device *device_list = resource->devices; acpi_status status = AE_OK; status = acpi_evaluate_object(resource->device->handle, "_ON", NULL, NULL); @@ -238,19 +238,15 @@ static int __acpi_power_on(struct acpi_power_resource *resource) ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned on\n", resource->name)); - while (device_list) { - acpi_power_on_device(device_list->device); - - device_list = device_list->next; - } - return 0; } static int acpi_power_on(acpi_handle handle) { int result = 0; + bool resume_device = false; struct acpi_power_resource *resource = NULL; + struct acpi_power_resource_device *device_list; result = acpi_power_get_context(handle, &resource); if (result) @@ -266,10 +262,25 @@ static int acpi_power_on(acpi_handle handle) result = __acpi_power_on(resource); if (result) resource->ref_count--; + else + resume_device = true; } mutex_unlock(&resource->resource_lock); + if (!resume_device) + return result; + + mutex_lock(&resource->devices_lock); + + device_list = resource->devices; + while (device_list) { + acpi_power_on_device(device_list->device); + device_list = device_list->next; + } + + mutex_unlock(&resource->devices_lock); + return result; } @@ -355,7 +366,7 @@ static void __acpi_power_resource_unregister_device(struct device *dev, if (acpi_power_get_context(res_handle, &resource)) return; - mutex_lock(&resource->resource_lock); + mutex_lock(&resource->devices_lock); prev = NULL; curr = resource->devices; while (curr) { @@ -372,7 +383,7 @@ static void __acpi_power_resource_unregister_device(struct device *dev, prev = curr; curr = curr->next; } - mutex_unlock(&resource->resource_lock); + mutex_unlock(&resource->devices_lock); } /* Unlink dev from all power resources in _PR0 */ @@ -414,10 +425,10 @@ static int __acpi_power_resource_register_device( power_resource_device->device = powered_device; - mutex_lock(&resource->resource_lock); + mutex_lock(&resource->devices_lock); power_resource_device->next = resource->devices; resource->devices = power_resource_device; - mutex_unlock(&resource->resource_lock); + mutex_unlock(&resource->devices_lock); return 0; } @@ -721,6 +732,7 @@ static int acpi_power_add(struct acpi_device *device) resource->device = device; mutex_init(&resource->resource_lock); + mutex_init(&resource->devices_lock); strcpy(resource->name, device->pnp.bus_id); strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME); strcpy(acpi_device_class(device), ACPI_POWER_CLASS); From f25b70613c048ceb1df052576fda03321ebf41cf Mon Sep 17 00:00:00 2001 From: Aaron Lu Date: Fri, 14 Sep 2012 20:54:44 +0200 Subject: [PATCH 3/3] ACPI / PM: Use KERN_DEBUG when no power resources are found commit a606dac368eed5696fb38e16b1394f1d049c09e9 adds support to link devices which have _PRx, if a device does not have _PRx, a warning message will be printed. This commit is for ZPODD on Intel ZPODD capable platforms, on other platforms, it has no problem if there is no power resource for this device, so a warning here is not appropriate, change it to debug. Reported-by: Borislav Petkov Signed-off-by: Aaron Lu Cc: stable@vger.kernel.org Signed-off-by: Rafael J. Wysocki --- drivers/acpi/power.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c index cc2a2dcff336..40e38a06ba85 100644 --- a/drivers/acpi/power.c +++ b/drivers/acpi/power.c @@ -473,7 +473,7 @@ int acpi_power_resource_register_device(struct device *dev, acpi_handle handle) return ret; no_power_resource: - printk(KERN_WARNING PREFIX "Invalid Power Resource to register!"); + printk(KERN_DEBUG PREFIX "Invalid Power Resource to register!"); return -ENODEV; } EXPORT_SYMBOL_GPL(acpi_power_resource_register_device);