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Date: Mon, 13 Feb 2012 21:48:04 +0100
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Lin Ming <ming.m.lin@...el.com>
Cc: Zhang Rui <rui.zhang@...el.com>, Jeff Garzik <jgarzik@...ox.com>,
Alan Stern <stern@...land.harvard.edu>,
Tejun Heo <tj@...nel.org>, Len Brown <lenb@...nel.org>,
linux-kernel@...r.kernel.org, linux-ide@...r.kernel.org,
linux-scsi@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [RFC PATCH 2/6] ACPI: Reference devices in ACPI Power Resource
On Monday, February 13, 2012, Lin Ming wrote:
> From: Zhang Rui <rui.zhang@...el.com>
>
> ACPI Power Resource can power on/off a couple of devices.
> Introduce interfaces to register/unregister a device to/from
> an ACPI Power Resource.
>
> Signed-off-by: Zhang Rui <rui.zhang@...el.com>
> ---
> drivers/acpi/power.c | 128 +++++++++++++++++++++++++++++++++++++++++++++++
> include/acpi/acpi_bus.h | 2 +
> 2 files changed, 130 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c
> index 0d681fb..a7e2305 100644
> --- a/drivers/acpi/power.c
> +++ b/drivers/acpi/power.c
> @@ -84,10 +84,25 @@ struct acpi_power_resource {
> u32 order;
> unsigned int ref_count;
> struct mutex resource_lock;
> + struct list_head devices; /* list for devices powered by this PR */
> };
>
> static struct list_head acpi_power_resource_list;
>
> +/*
> + * When a power resource is turned on, all the devices are put to an uninitialized
> + * state although their ACPI states are still D0.
> + * To handle this, we need to keep a list of all devices powered by the power resource,
> + * and resume all of them.
> + * Currently, we only support this case:
> + * 1) multiple devices share the same power resoruce,
> + * 2) One device uses One Power Resource ONLY.
This is incorrect. We actually support all combinations. However, we don't
generally support checking what devices depend on the given power resource.
> + */
> +struct acpi_powered_device {
> + struct list_head node;
> + struct device *dev;
> +};
> +
> /* --------------------------------------------------------------------------
> Power Resource Management
> -------------------------------------------------------------------------- */
> @@ -455,6 +470,118 @@ int acpi_disable_wakeup_device_power(struct acpi_device *dev)
> Device Power Management
> -------------------------------------------------------------------------- */
>
> +int acpi_power_resource_register_device(struct device *dev, acpi_handle handle)
> +{
> + struct acpi_power_resource *resource;
> + struct acpi_device *acpi_dev, *res_dev;
> + acpi_handle res_handle = NULL;
> + struct acpi_powered_device *apd;
> + int i;
> + int ret;
> +
> + if (!handle || !dev)
> + return -EINVAL;
> +
> + ret = acpi_bus_get_device(handle, &acpi_dev);
> + if (ret)
> + goto no_power_resource;
> +
> + if (!acpi_dev->power.flags.power_resources)
> + goto no_power_resource;
> +
> + for (i = 0; i <= ACPI_STATE_D3; i++) {
> + struct acpi_device_power_state *ps = &acpi_dev->power.states[i];
> +
> + if (!ps->flags.valid)
> + continue;
> +
> + if (ps->resources.count > 1)
> + return 0;
> +
> + if (!res_handle)
> + res_handle = ps->resources.handles[0];
> + else if (res_handle != ps->resources.handles[0])
> + return 0;
> + }
I'm not sure what the above checks are needed for. It seems that this function
will only be called from acpi_bus_add_power_resource() (which needs to be
modified for this purpose, BTW), so it doesn't need to check all those things
(those checks have been made already).
> +
> + ret = acpi_bus_get_device(res_handle, &res_dev);
> + if (ret)
> + goto no_power_resource;
> +
> + resource = res_dev->driver_data;
> + if (!resource)
> + goto no_power_resource;
> +
> + apd = kzalloc(sizeof(struct acpi_powered_device), GFP_KERNEL);
> + if (!apd)
> + return -ENOMEM;
> +
> + apd->dev = dev;
> + mutex_lock(&resource->resource_lock);
> + list_add_tail(&apd->node, &resource->devices);
> + mutex_unlock(&resource->resource_lock);
> + printk(KERN_INFO PREFIX "Device %s uses Power Resource %s\n", dev->kobj.name, acpi_device_name(res_dev));
> +
> + return 0;
> +
> +no_power_resource:
> + printk(KERN_WARNING PREFIX "Invalid Power Resource to register!");
> + return -ENODEV;
> +}
> +
> +void acpi_power_resource_unregister_device(struct device *dev, acpi_handle handle)
> +{
Who is supposed to call this one?
> + struct acpi_power_resource *resource;
> + struct acpi_device *acpi_dev, *res_dev;
> + acpi_handle res_handle = NULL;
> + struct acpi_powered_device *apd, *tmp;
> + int i;
> + int ret;
> +
> + if (!handle || !dev)
> + return;
> +
> + ret = acpi_bus_get_device(handle, &acpi_dev);
> + if (ret)
> + return;
> +
> + if (!acpi_dev->power.flags.power_resources)
> + return;
> +
> + for (i = 0; i <= ACPI_STATE_D3; i++) {
> + struct acpi_device_power_state *ps = &acpi_dev->power.states[i];
> +
> + if (!ps->flags.valid)
> + continue;
> +
> + if (ps->resources.count > 1)
> + return;
> +
> + res_handle = ps->resources.handles[0];
> + break;
> + }
> +
> + if (!res_handle)
> + return;
> +
> + ret = acpi_bus_get_device(res_handle, &res_dev);
> + if (ret)
> + return;
> +
> + resource = res_dev->driver_data;
> + if (!resource)
> + return;
> +
> + mutex_lock(&resource->resource_lock);
> + list_for_each_entry_safe(apd, tmp, &resource->devices, node) {
> + if (apd->dev == dev) {
> + list_del(&apd->node);
> + kfree(apd);
> + }
> + }
> + mutex_unlock(&resource->resource_lock);
> +}
> +
> int acpi_power_get_inferred_state(struct acpi_device *device, int *state)
> {
> int result = 0;
> @@ -550,6 +677,7 @@ static int acpi_power_add(struct acpi_device *device)
>
> resource->device = device;
> mutex_init(&resource->resource_lock);
> + INIT_LIST_HEAD(&resource->devices);
> strcpy(resource->name, device->pnp.bus_id);
> strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
> strcpy(acpi_device_class(device), ACPI_POWER_CLASS);
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index 6cd5b64..32fb899 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -322,6 +322,8 @@ int acpi_bus_get_status(struct acpi_device *device);
> int acpi_bus_set_power(acpi_handle handle, int state);
> int acpi_bus_update_power(acpi_handle handle, int *state_p);
> bool acpi_bus_power_manageable(acpi_handle handle);
> +int acpi_power_resource_register_device(struct device *dev, acpi_handle handle);
> +void acpi_power_resource_unregister_device(struct device *dev, acpi_handle handle);
> bool acpi_bus_can_wakeup(acpi_handle handle);
> #ifdef CONFIG_ACPI_PROC_EVENT
> int acpi_bus_generate_proc_event(struct acpi_device *device, u8 type, int data);
Thanks,
Rafael
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