On Wed, 28 Mar 2012, Lan Tianyu wrote:
> The usb port is a device in the acpi table but it's not in the linux
> usb subsystem. USB hub port doesn't have struct device. So the acpi
> glue framework only can cover the usb port connected with usb device
> and store the acpi handle to struct device.archdata.acpi_handle. This
> patch gets the hub port's acpi_handle and store it in the port's platform_data
> to resolve no attached device no binding problem. The acpi method "_UPC"
> and "_PLD" can be accessed without attached device.
You can merge this patch with the previous one. As it stands now, the
previous patch adds new routines but no callers.
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index ac7bd89..97b8993 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -1239,6 +1239,7 @@ static int hub_configure(struct usb_hub *hub,
> hub->indicator [0] = INDICATOR_CYCLE;
>
> hub_activate(hub, HUB_INIT);
> + usb_acpi_bind_hub_ports(hdev);
> return 0;
You probably should put usb_acpi_bind_hub_ports before hub_activate
instead of after. The hub can start to operate as soon as hub_activate
runs.
> --- a/drivers/usb/core/usb-acpi.c
> +++ b/drivers/usb/core/usb-acpi.c
> @@ -82,7 +82,16 @@ static int usb_acpi_find_device(struct device *dev, acpi_handle *handle)
> if (!parent_handle)
> return -ENODEV;
>
> - *handle = acpi_get_child(parent_handle, udev->portnum);
> + /**
> + * The root hub's acpi handle is got from acpi method.
> + * Other device's acpi handle can be got from the usb hub
> + * port's platform_data.
> + */
> + if (!udev->parent)
> + *handle = acpi_get_child(parent_handle, udev->portnum);
> + else
> + usb_get_hub_port_platform_data(udev->parent, udev->portnum,
> + (unsigned long *)handle);
>
> if (!*handle)
What happens if usb_get_hub_port_platform_data returns an error? You
don't check the error code, and then handle never gets assigned any
value. So the test "if (!*handle)" won't work right.
Instead of returning an error code, make usb_get_hub_port_platform_data
return the data directly.
> return -ENODEV;
> @@ -105,6 +114,33 @@ static struct acpi_bus_type usb_acpi_bus = {
> .find_device = usb_acpi_find_device,
> };
>
> +int usb_acpi_bind_hub_ports(struct usb_device *hdev)
> +{
> + acpi_handle hub_handle = NULL;
> + acpi_handle port_handle = NULL;
> + struct device *dev = &hdev->dev;
> + int i;
> +
> + hub_handle = DEVICE_ACPI_HANDLE(dev);
> + if (!hub_handle)
> + return -ENODEV;
> +
> + /**
> + * The usb hub port is not a device in the usb subsystem but it is a device
> + * in the acpi table. Store its acpi handle in the platform data of usb
> + * hub port.
> + */
> + for (i = 1; i <= hdev->maxchild; i++) {
> + port_handle = acpi_get_child(hub_handle, i);
> + if (!port_handle)
> + continue;
> + if (usb_set_hub_port_platform_data(hdev, i,
> + (unsigned long)port_handle) < 0)
> + return -ENODEV;
Similarly, make usb_set_hub_port_platform_data return void. There's no
reason to check for errors here; they can never happen.
Alan Stern
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