On Thu, Mar 28, 2013 at 01:11:02AM +0800, Lan Tianyu wrote:
> Some devices' firmware will be broken at some points. Power down
> and power on device can help device to rework in this case.
>
> This patch is to add ioctl cmd USBDEVFS_POWER_RESET for usbfs node
> to repower usb device. First, call hub_port_logical_disconnect() to
> disconnect device. Second, Power down and up usb port.
I don't think this is the right approach. We want to be able to power
off a port, even if no devices are attached. One of the use case
scenarios we discussed was allowing distros to turn off empty USB ports
according to some policy (e.g. screen blank, lost bluetooth connection
to their phone that indicates the user walked away from the computer,
server admin wants to save power, etc).
With the current patches in 3.9, I don't see a way we can do that. The
ports have power/control, which can only be set to 'on' or 'auto'. You
should add an 'off' option to that file.
I don't particularly care if usbfs gets a new port power ioctl, I just
want the port power sysfs files to allow power off of an empty port.
> This patch is also helpful fo some QAs who want to do hcd's memleak
> test(Plug and unplug device thousand times.)
What we'd like to also do in our internal Intel QA is measure the USB
host power, manually power off all ports, and ensure the host power
drops. That way we can be sure the BIOS and your ACPI code is working
properly.
Sarah Sharp
>
> Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
> ---
> drivers/usb/core/devio.c | 13 +++++++++++++
> drivers/usb/core/hub.c | 16 ++++++++++++++++
> drivers/usb/core/usb.h | 2 ++
> include/uapi/linux/usbdevice_fs.h | 1 +
> 4 files changed, 32 insertions(+)
>
> diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
> index 8823e98..a76b326 100644
> --- a/drivers/usb/core/devio.c
> +++ b/drivers/usb/core/devio.c
> @@ -1102,6 +1102,14 @@ static int proc_resetdevice(struct dev_state *ps)
> return usb_reset_device(ps->dev);
> }
>
> +static int proc_resetdevicepower(struct dev_state *ps)
> +{
> + struct usb_device *udev = ps->dev;
> + struct usb_device *hdev = udev->parent;
> +
> + return usb_hub_port_power_reset(hdev, udev->portnum);
> +}
> +
> static int proc_setintf(struct dev_state *ps, void __user *arg)
> {
> struct usbdevfs_setinterface setintf;
> @@ -2011,6 +2019,11 @@ static long usbdev_do_ioctl(struct file *file, unsigned int cmd,
> ret = proc_resetdevice(ps);
> break;
>
> + case USBDEVFS_POWER_RESET:
> + snoop(&dev->dev, "%s: RESET POWER\n", __func__);
> + ret = proc_resetdevicepower(ps);
> + break;
> +
> case USBDEVFS_CLEAR_HALT:
> snoop(&dev->dev, "%s: CLEAR_HALT\n", __func__);
> ret = proc_clearhalt(ps, p);
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index 6b7f5b9..c228e69 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -114,6 +114,7 @@ EXPORT_SYMBOL_GPL(ehci_cf_port_reset_rwsem);
> #define HUB_DEBOUNCE_STABLE 100
>
> static int usb_reset_and_verify_device(struct usb_device *udev);
> +static void hub_port_logical_disconnect(struct usb_hub *hub, int port1);
>
> static inline char *portspeed(struct usb_hub *hub, int portstatus)
> {
> @@ -741,6 +742,21 @@ int usb_hub_set_port_power(struct usb_device *hdev, int port1,
> return ret;
> }
>
> +int usb_hub_port_power_reset(struct usb_device *hdev, int port1)
> +{
> + struct usb_hub *hub = usb_hub_to_struct_hub(hdev);
> + struct usb_interface *intf = to_usb_interface(hub->intfdev);
> + int ret;
> +
> + usb_autopm_get_interface(intf);
> + hub_port_logical_disconnect(hub, port1);
> + ret = usb_hub_set_port_power(hdev, port1, false);
> + ret |= usb_hub_set_port_power(hdev, port1, true);
> + usb_autopm_put_interface(intf);
> +
> + return ret;
> +}
> +
> /**
> * usb_hub_clear_tt_buffer - clear control/bulk TT state in high speed hub
> * @urb: an URB associated with the failed or incomplete split transaction
> diff --git a/drivers/usb/core/usb.h b/drivers/usb/core/usb.h
> index a7f20bd..4e7785c 100644
> --- a/drivers/usb/core/usb.h
> +++ b/drivers/usb/core/usb.h
> @@ -185,6 +185,8 @@ extern void usb_set_hub_port_connect_type(struct usb_device *hdev, int port1,
> enum usb_port_connect_type type);
> extern void usb_hub_adjust_deviceremovable(struct usb_device *hdev,
> struct usb_hub_descriptor *desc);
> +extern int usb_hub_port_power_reset(struct usb_device *hdev,
> + int port1);
>
> #ifdef CONFIG_ACPI
> extern int usb_acpi_register(void);
> diff --git a/include/uapi/linux/usbdevice_fs.h b/include/uapi/linux/usbdevice_fs.h
> index 0c65e4b..b6e0d17 100644
> --- a/include/uapi/linux/usbdevice_fs.h
> +++ b/include/uapi/linux/usbdevice_fs.h
> @@ -176,5 +176,6 @@ struct usbdevfs_disconnect_claim {
> #define USBDEVFS_RELEASE_PORT _IOR('U', 25, unsigned int)
> #define USBDEVFS_GET_CAPABILITIES _IOR('U', 26, __u32)
> #define USBDEVFS_DISCONNECT_CLAIM _IOR('U', 27, struct usbdevfs_disconnect_claim)
> +#define USBDEVFS_POWER_RESET _IO('U', 28)
>
> #endif /* _UAPI_LINUX_USBDEVICE_FS_H */
> --
> 1.7.9.5
>
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