USB: add power/level sysfs attribute
This patch (as874) adds another piece to the user-visible part of the
USB autosuspend interface. The new power/level sysfs attribute allows
users to force the device on (with autosuspend off), force the device
to sleep (with autoresume off), or return to normal automatic operation.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 884179f..9b6a60f 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -872,8 +872,10 @@
done:
// dev_dbg(&udev->dev, "%s: status %d\n", __FUNCTION__, status);
- if (status == 0)
+ if (status == 0) {
+ udev->autoresume_disabled = 0;
udev->dev.power.power_state.event = PM_EVENT_ON;
+ }
return status;
}
@@ -970,7 +972,7 @@
udev->do_remote_wakeup = device_may_wakeup(&udev->dev);
if (udev->pm_usage_cnt > 0)
return -EBUSY;
- if (udev->autosuspend_delay < 0)
+ if (udev->autosuspend_delay < 0 || udev->autosuspend_disabled)
return -EPERM;
if (udev->actconfig) {
@@ -1116,6 +1118,8 @@
struct usb_interface *intf;
struct usb_device *parent = udev->parent;
+ if (udev->auto_pm && udev->autoresume_disabled)
+ return -EPERM;
cancel_delayed_work(&udev->autosuspend);
if (udev->state == USB_STATE_NOTATTACHED)
return -ENODEV;
@@ -1486,9 +1490,14 @@
static int usb_resume(struct device *dev)
{
+ struct usb_device *udev;
+
if (!is_usb_device(dev)) /* Ignore PM for interfaces */
return 0;
- return usb_external_resume_device(to_usb_device(dev));
+ udev = to_usb_device(dev);
+ if (udev->autoresume_disabled)
+ return -EPERM;
+ return usb_external_resume_device(udev);
}
#else
diff --git a/drivers/usb/core/quirks.c b/drivers/usb/core/quirks.c
index f08ec85..739f520 100644
--- a/drivers/usb/core/quirks.c
+++ b/drivers/usb/core/quirks.c
@@ -42,7 +42,7 @@
{
#ifdef CONFIG_USB_SUSPEND
/* disable autosuspend, but allow the user to re-enable it via sysfs */
- udev->autosuspend_delay = 0;
+ udev->autosuspend_disabled = 1;
#endif
}
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index 731001f..2ea47a3 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -11,6 +11,7 @@
#include <linux/kernel.h>
+#include <linux/string.h>
#include <linux/usb.h>
#include "usb.h"
@@ -184,9 +185,8 @@
if (value >= 0)
usb_try_autosuspend_device(udev);
else {
- usb_lock_device(udev);
- usb_external_resume_device(udev);
- usb_unlock_device(udev);
+ if (usb_autoresume_device(udev) == 0)
+ usb_autosuspend_device(udev);
}
return count;
}
@@ -194,22 +194,95 @@
static DEVICE_ATTR(autosuspend, S_IRUGO | S_IWUSR,
show_autosuspend, set_autosuspend);
+static const char on_string[] = "on";
+static const char auto_string[] = "auto";
+static const char suspend_string[] = "suspend";
+
+static ssize_t
+show_level(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct usb_device *udev = to_usb_device(dev);
+ const char *p = auto_string;
+
+ if (udev->state == USB_STATE_SUSPENDED) {
+ if (udev->autoresume_disabled)
+ p = suspend_string;
+ } else {
+ if (udev->autosuspend_disabled)
+ p = on_string;
+ }
+ return sprintf(buf, "%s\n", p);
+}
+
+static ssize_t
+set_level(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct usb_device *udev = to_usb_device(dev);
+ int len = count;
+ char *cp;
+ int rc = 0;
+
+ cp = memchr(buf, '\n', count);
+ if (cp)
+ len = cp - buf;
+
+ usb_lock_device(udev);
+
+ /* Setting the flags without calling usb_pm_lock is a subject to
+ * races, but who cares...
+ */
+ if (len == sizeof on_string - 1 &&
+ strncmp(buf, on_string, len) == 0) {
+ udev->autosuspend_disabled = 1;
+ udev->autoresume_disabled = 0;
+ rc = usb_external_resume_device(udev);
+
+ } else if (len == sizeof auto_string - 1 &&
+ strncmp(buf, auto_string, len) == 0) {
+ udev->autosuspend_disabled = 0;
+ udev->autoresume_disabled = 0;
+ rc = usb_external_resume_device(udev);
+
+ } else if (len == sizeof suspend_string - 1 &&
+ strncmp(buf, suspend_string, len) == 0) {
+ udev->autosuspend_disabled = 0;
+ udev->autoresume_disabled = 1;
+ rc = usb_external_suspend_device(udev, PMSG_SUSPEND);
+
+ } else
+ rc = -EINVAL;
+
+ usb_unlock_device(udev);
+ return (rc < 0 ? rc : count);
+}
+
+static DEVICE_ATTR(level, S_IRUGO | S_IWUSR, show_level, set_level);
+
static char power_group[] = "power";
static int add_power_attributes(struct device *dev)
{
int rc = 0;
- if (is_usb_device(dev))
+ if (is_usb_device(dev)) {
rc = sysfs_add_file_to_group(&dev->kobj,
&dev_attr_autosuspend.attr,
power_group);
+ if (rc == 0)
+ rc = sysfs_add_file_to_group(&dev->kobj,
+ &dev_attr_level.attr,
+ power_group);
+ }
return rc;
}
static void remove_power_attributes(struct device *dev)
{
sysfs_remove_file_from_group(&dev->kobj,
+ &dev_attr_level.attr,
+ power_group);
+ sysfs_remove_file_from_group(&dev->kobj,
&dev_attr_autosuspend.attr,
power_group);
}