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USB: export autosuspend delay in sysfs

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This patch (as861) adds sysfs attributes to expose the autosuspend
delay value for each USB device.  If the user changes the delay from 0
(no autosuspend) to a positive value, an autosuspend is attempted.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Alan Stern 2007-02-20 15:03:32 -05:00 committed by Greg Kroah-Hartman
parent dfa87c824a
commit 19c262391c
3 changed files with 87 additions and 1 deletions
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20
drivers/usb/core/driver.c
View file

@ -1224,6 +1224,26 @@ void usb_autosuspend_device(struct usb_device *udev)
// __FUNCTION__, udev->pm_usage_cnt);
}
/**
* usb_try_autosuspend_device - attempt an autosuspend of a USB device and its interfaces
* @udev: the usb_device to autosuspend
*
* This routine should be called when a core subsystem thinks @udev may
* be ready to autosuspend.
*
* @udev's usage counter left unchanged. If it or any of the usage counters
* for an active interface is greater than 0, or autosuspend is not allowed
* for any other reason, no autosuspend request will be queued.
*
* This routine can run only in process context.
*/
void usb_try_autosuspend_device(struct usb_device *udev)
{
usb_autopm_do_device(udev, 0);
// dev_dbg(&udev->dev, "%s: cnt %d\n",
// __FUNCTION__, udev->pm_usage_cnt);
}
/**
* usb_autoresume_device - immediately autoresume a USB device and its interfaces
* @udev: the usb_device to autoresume

64
drivers/usb/core/sysfs.c
View file

@ -158,6 +158,65 @@ show_quirks(struct device *dev, struct device_attribute *attr, char *buf)
}
static DEVICE_ATTR(quirks, S_IRUGO, show_quirks, NULL);
#ifdef CONFIG_USB_SUSPEND
static ssize_t
show_autosuspend(struct device *dev, struct device_attribute *attr, char *buf)
{
struct usb_device *udev = to_usb_device(dev);
return sprintf(buf, "%u\n", udev->autosuspend_delay / HZ);
}
static ssize_t
set_autosuspend(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct usb_device *udev = to_usb_device(dev);
unsigned value, old;
if (sscanf(buf, "%u", &value) != 1 || value >= INT_MAX/HZ)
return -EINVAL;
value *= HZ;
old = udev->autosuspend_delay;
udev->autosuspend_delay = value;
if (value > 0 && old == 0)
usb_try_autosuspend_device(udev);
return count;
}
static DEVICE_ATTR(autosuspend, S_IRUGO | S_IWUSR,
show_autosuspend, set_autosuspend);
static char power_group[] = "power";
static int add_power_attributes(struct device *dev)
{
int rc = 0;
if (is_usb_device(dev))
rc = sysfs_add_file_to_group(&dev->kobj,
&dev_attr_autosuspend.attr,
power_group);
return rc;
}
static void remove_power_attributes(struct device *dev)
{
sysfs_remove_file_from_group(&dev->kobj,
&dev_attr_autosuspend.attr,
power_group);
}
#else
#define add_power_attributes(dev) 0
#define remove_power_attributes(dev) do {} while (0)
#endif /* CONFIG_USB_SUSPEND */
/* Descriptor fields */
#define usb_descriptor_attr_le16(field, format_string) \
static ssize_t \
@ -230,6 +289,10 @@ int usb_create_sysfs_dev_files(struct usb_device *udev)
if (retval)
return retval;
retval = add_power_attributes(dev);
if (retval)
goto error;
if (udev->manufacturer) {
retval = device_create_file(dev, &dev_attr_manufacturer);
if (retval)
@ -262,6 +325,7 @@ void usb_remove_sysfs_dev_files(struct usb_device *udev)
device_remove_file(dev, &dev_attr_manufacturer);
device_remove_file(dev, &dev_attr_product);
device_remove_file(dev, &dev_attr_serial);
remove_power_attributes(dev);
sysfs_remove_group(&dev->kobj, &dev_attr_grp);
}

4
drivers/usb/core/usb.h
View file

@ -66,11 +66,13 @@ static inline void usb_pm_unlock(struct usb_device *udev) {}
#ifdef CONFIG_USB_SUSPEND
extern void usb_autosuspend_device(struct usb_device *udev);
extern void usb_try_autosuspend_device(struct usb_device *udev);
extern int usb_autoresume_device(struct usb_device *udev);
#else
#define usb_autosuspend_device(udev) do {} while (0)
#define usb_autosuspend_device(udev) do {} while (0)
#define usb_try_autosuspend_device(udev) do {} while (0)
static inline int usb_autoresume_device(struct usb_device *udev)
{
return 0;