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>
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index 11a3c16..df6c8a0 100644
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -85,3 +85,19 @@
Users:
PowerTOP <power@bughost.org>
http://www.lesswatts.org/projects/powertop/
+
+What: /sys/bus/usb/device/<busnum>-<devnum>...:<config num>-<interface num>/supports_autosuspend
+Date: January 2008
+KernelVersion: 2.6.27
+Contact: Sarah Sharp <sarah.a.sharp@intel.com>
+Description:
+ When read, this file returns 1 if the interface driver
+ for this interface supports autosuspend. It also
+ returns 1 if no driver has claimed this interface, as an
+ unclaimed interface will not stop the device from being
+ autosuspended if all other interface drivers are idle.
+ The file returns 0 if autosuspend support has not been
+ added to the driver.
+Users:
+ USB PM tool
+ git://git.moblin.org/users/sarah/usb-pm-tool/
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index 5e1f5d5..f66fba1 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -743,6 +743,29 @@
}
static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
+static ssize_t show_supports_autosuspend(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct usb_interface *intf;
+ struct usb_device *udev;
+ int ret;
+
+ intf = to_usb_interface(dev);
+ udev = interface_to_usbdev(intf);
+
+ usb_lock_device(udev);
+ /* Devices will be autosuspended even when an interface isn't claimed */
+ if (!intf->dev.driver ||
+ to_usb_driver(intf->dev.driver)->supports_autosuspend)
+ ret = sprintf(buf, "%u\n", 1);
+ else
+ ret = sprintf(buf, "%u\n", 0);
+ usb_unlock_device(udev);
+
+ return ret;
+}
+static DEVICE_ATTR(supports_autosuspend, S_IRUGO, show_supports_autosuspend, NULL);
+
static struct attribute *intf_attrs[] = {
&dev_attr_bInterfaceNumber.attr,
&dev_attr_bAlternateSetting.attr,
@@ -751,6 +774,7 @@
&dev_attr_bInterfaceSubClass.attr,
&dev_attr_bInterfaceProtocol.attr,
&dev_attr_modalias.attr,
+ &dev_attr_supports_autosuspend.attr,
NULL,
};
static struct attribute_group intf_attr_grp = {
