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Date: Mon, 17 Dec 2012 17:08:17 -0700
From: Toshi Kani <toshi.kani@...com>
To: "Rafael J. Wysocki" <rjw@...k.pl>
Cc: ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
Bjorn Helgaas <bhelgaas@...gle.com>,
LKML <linux-kernel@...r.kernel.org>, linux-pci@...r.kernel.org,
Yinghai Lu <yinghai@...nel.org>,
Myron Stowe <myron.stowe@...hat.com>,
Yijing Wang <wangyijing0307@...il.com>,
Jiang Liu <liuj97@...il.com>
Subject: Re: [PATCH rev.2 1/6] ACPI: Separate adding ACPI device objects
from probing ACPI drivers
On Thu, 2012-12-13 at 23:17 +0100, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>
(snip)
> struct acpi_device_ops {
> Index: linux/drivers/acpi/scan.c
> ===================================================================
> --- linux.orig/drivers/acpi/scan.c
> +++ linux/drivers/acpi/scan.c
> @@ -494,7 +494,8 @@ static int acpi_bus_match(struct device
> struct acpi_device *acpi_dev = to_acpi_device(dev);
> struct acpi_driver *acpi_drv = to_acpi_driver(drv);
>
> - return !acpi_match_device_ids(acpi_dev, acpi_drv->ids);
> + return acpi_dev->bus_ops.acpi_op_match
> + && !acpi_match_device_ids(acpi_dev, acpi_drv->ids);
> }
>
> static int acpi_device_uevent(struct device *dev, struct kobj_uevent_env *env)
> @@ -1418,6 +1419,17 @@ static int acpi_bus_remove(struct acpi_d
> return 0;
> }
>
> +/*
> + * acpi_hot_add_bind - Bind _ADR-based devices on hot-add.
> + * @device: ACPI device node to bind.
> + */
> +static void acpi_hot_add_bind(struct acpi_device *device)
> +{
> + if (device->flags.bus_address
> + && device->parent && device->parent->ops.bind)
> + device->parent->ops.bind(device);
> +}
> +
> static int acpi_add_single_object(struct acpi_device **child,
> acpi_handle handle, int type,
> unsigned long long sta,
> @@ -1490,13 +1502,8 @@ static int acpi_add_single_object(struct
>
> result = acpi_device_register(device);
>
> - /*
> - * Bind _ADR-Based Devices when hot add
> - */
> - if (device->flags.bus_address) {
> - if (device->parent && device->parent->ops.bind)
> - device->parent->ops.bind(device);
> - }
I think the original code above is hot-add only because ops.bind is not
set at boot since the acpi_pci driver has not been registered yet. It
seems that acpi_pci_bridge_scan() called from acpi_pci_root_add() takes
care of the binding.
This brings me a question for acpi_bus_probe_start() below...
> + if (device->bus_ops.acpi_op_match)
> + acpi_hot_add_bind(device);
>
> end:
> if (!result) {
> @@ -1522,6 +1529,7 @@ static void acpi_bus_add_power_resource(
> struct acpi_bus_ops ops = {
> .acpi_op_add = 1,
> .acpi_op_start = 1,
> + .acpi_op_match = 1,
> };
> struct acpi_device *device = NULL;
>
> @@ -1574,9 +1582,9 @@ static acpi_status acpi_bus_check_add(ac
> void *context, void **return_value)
> {
> struct acpi_bus_ops *ops = context;
> + struct acpi_device *device = NULL;
> int type;
> unsigned long long sta;
> - struct acpi_device *device;
> acpi_status status;
> int result;
>
> @@ -1596,52 +1604,86 @@ static acpi_status acpi_bus_check_add(ac
> return AE_CTRL_DEPTH;
> }
>
> - /*
> - * We may already have an acpi_device from a previous enumeration. If
> - * so, we needn't add it again, but we may still have to start it.
> - */
> - device = NULL;
> acpi_bus_get_device(handle, &device);
> if (ops->acpi_op_add && !device) {
> - acpi_add_single_object(&device, handle, type, sta, ops);
> - /* Is the device a known good platform device? */
> - if (device
> - && !acpi_match_device_ids(device, acpi_platform_device_ids))
> - acpi_create_platform_device(device);
> - }
> -
> - if (!device)
> - return AE_CTRL_DEPTH;
> + struct acpi_bus_ops add_ops = *ops;
>
> - if (ops->acpi_op_start && !(ops->acpi_op_add)) {
> - status = acpi_start_single_object(device);
> - if (ACPI_FAILURE(status))
> + add_ops.acpi_op_match = 0;
> + acpi_add_single_object(&device, handle, type, sta, &add_ops);
> + if (!device)
> return AE_CTRL_DEPTH;
> +
> + device->bus_ops.acpi_op_match = 1;
> }
>
> if (!*return_value)
> *return_value = device;
> +
> return AE_OK;
> }
>
> +static acpi_status acpi_bus_probe_start(acpi_handle handle, u32 lvl,
> + void *context, void **not_used)
> +{
> + struct acpi_bus_ops *ops = context;
> + acpi_status status = AE_OK;
> + struct acpi_device *device;
> + unsigned long long sta_not_used;
> + int type_not_used;
> +
> + /*
> + * Ignore errors ignored by acpi_bus_check_add() to avoid terminating
"ignore" seems duplicated.
> + * namespace walks prematurely.
> + */
> + if (acpi_bus_type_and_status(handle, &type_not_used, &sta_not_used))
> + return AE_OK;
> +
> + if (acpi_bus_get_device(handle, &device))
> + return AE_CTRL_DEPTH;
> +
> + if (ops->acpi_op_add) {
> + if (!acpi_match_device_ids(device, acpi_platform_device_ids)) {
> + /* This is a known good platform device. */
> + acpi_create_platform_device(device);
> + } else {
> + int ret = device_attach(&device->dev);
> + acpi_hot_add_bind(device);
Since acpi_pci_root_add() is called by device_attach(), I think this
acpi_hot_add_bind() calls .bind() of a device at boot since its .bind()
may be set. Is that correct? If so, how does it coordinate with the
bind procedure in acpi_pci_bridge_scan()?
Thanks,
-Toshi
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