USB: Export if an interface driver supports autosuspend.
Create a new sysfs file per interface named supports_autosuspend. This file returns true if an interface driver's .supports_autosuspend flag is set. It also returns true if the interface is unclaimed (since the USB core will autosuspend a device if an interface is not claimed). This new sysfs file will be useful for user space scripts to test whether a USB device correctly auto-suspends. Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Cc: Oliver Neukum <oliver@neukum.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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@ -85,3 +85,19 @@ Description:
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Users:
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PowerTOP <power@bughost.org>
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http://www.lesswatts.org/projects/powertop/
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What: /sys/bus/usb/device/<busnum>-<devnum>...:<config num>-<interface num>/supports_autosuspend
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Date: January 2008
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KernelVersion: 2.6.27
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Contact: Sarah Sharp <sarah.a.sharp@intel.com>
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Description:
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When read, this file returns 1 if the interface driver
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for this interface supports autosuspend. It also
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returns 1 if no driver has claimed this interface, as an
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unclaimed interface will not stop the device from being
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autosuspended if all other interface drivers are idle.
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The file returns 0 if autosuspend support has not been
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added to the driver.
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Users:
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USB PM tool
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git://git.moblin.org/users/sarah/usb-pm-tool/
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@ -743,6 +743,29 @@ static ssize_t show_modalias(struct device *dev,
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}
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static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
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static ssize_t show_supports_autosuspend(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct usb_interface *intf;
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struct usb_device *udev;
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int ret;
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intf = to_usb_interface(dev);
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udev = interface_to_usbdev(intf);
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usb_lock_device(udev);
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/* Devices will be autosuspended even when an interface isn't claimed */
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if (!intf->dev.driver ||
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to_usb_driver(intf->dev.driver)->supports_autosuspend)
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ret = sprintf(buf, "%u\n", 1);
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else
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ret = sprintf(buf, "%u\n", 0);
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usb_unlock_device(udev);
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return ret;
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}
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static DEVICE_ATTR(supports_autosuspend, S_IRUGO, show_supports_autosuspend, NULL);
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static struct attribute *intf_attrs[] = {
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&dev_attr_bInterfaceNumber.attr,
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&dev_attr_bAlternateSetting.attr,
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@ -751,6 +774,7 @@ static struct attribute *intf_attrs[] = {
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&dev_attr_bInterfaceSubClass.attr,
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&dev_attr_bInterfaceProtocol.attr,
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&dev_attr_modalias.attr,
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&dev_attr_supports_autosuspend.attr,
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NULL,
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};
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static struct attribute_group intf_attr_grp = {
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