From stern@rowland.harvard.edu Tue Mar 13 13:39:23 2007 Date: Tue, 13 Mar 2007 16:39:15 -0400 (EDT) From: Alan Stern To: Greg KH Subject: USB: Allow autosuspend delay to equal 0 Message-ID: This patch (as867) adds an entry for the new power/autosuspend attribute in Documentation/ABI/testing, and it changes the behavior of the delay value. Now a delay of 0 means to autosuspend as soon as possible, and negative values will prevent autosuspend. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-bus-usb | 15 +++++++++++++++ Documentation/kernel-parameters.txt | 2 +- drivers/usb/core/driver.c | 2 +- drivers/usb/core/sysfs.c | 16 ++++++++++------ drivers/usb/core/usb.c | 2 +- include/linux/usb.h | 2 +- 6 files changed, 29 insertions(+), 10 deletions(-) --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-usb @@ -0,0 +1,15 @@ +What: /sys/bus/usb/devices/.../power/autosuspend +Date: March 2007 +KernelVersion: 2.6.21 +Contact: Alan Stern +Description: + Each USB device directory will contain a file named + power/autosuspend. This file holds the time (in seconds) + the device must be idle before it will be autosuspended. + 0 means the device will be autosuspended as soon as + possible. Negative values will prevent the device from + being autosuspended at all, and writing a negative value + will resume the device if it is already suspended. + + The autosuspend delay for newly-created devices is set to + the value of the usbcore.autosuspend module parameter. --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1781,7 +1781,7 @@ and is between 256 and 4096 characters. for newly-detected USB devices (default 2). This is the time required before an idle device will be autosuspended. Devices for which the delay is set - to 0 won't be autosuspended at all. + to a negative value won't be autosuspended at all. usbhid.mousepoll= [USBHID] The interval which mice are to be polled at. --- a/drivers/usb/core/driver.c +++ b/drivers/usb/core/driver.c @@ -970,7 +970,7 @@ static int autosuspend_check(struct usb_ udev->do_remote_wakeup = device_may_wakeup(&udev->dev); if (udev->pm_usage_cnt > 0) return -EBUSY; - if (!udev->autosuspend_delay) + if (udev->autosuspend_delay < 0) return -EPERM; if (udev->actconfig) { --- a/drivers/usb/core/sysfs.c +++ b/drivers/usb/core/sysfs.c @@ -165,7 +165,7 @@ show_autosuspend(struct device *dev, str { struct usb_device *udev = to_usb_device(dev); - return sprintf(buf, "%u\n", udev->autosuspend_delay / HZ); + return sprintf(buf, "%d\n", udev->autosuspend_delay / HZ); } static ssize_t @@ -173,17 +173,21 @@ set_autosuspend(struct device *dev, stru const char *buf, size_t count) { struct usb_device *udev = to_usb_device(dev); - unsigned value, old; + int value; - if (sscanf(buf, "%u", &value) != 1 || value >= INT_MAX/HZ) + if (sscanf(buf, "%d", &value) != 1 || value >= INT_MAX/HZ || + value <= - INT_MAX/HZ) return -EINVAL; value *= HZ; - old = udev->autosuspend_delay; udev->autosuspend_delay = value; - if (value > 0 && old == 0) + if (value >= 0) usb_try_autosuspend_device(udev); - + else { + usb_lock_device(udev); + usb_external_resume_device(udev); + usb_unlock_device(udev); + } return count; } --- a/drivers/usb/core/usb.c +++ b/drivers/usb/core/usb.c @@ -55,7 +55,7 @@ struct workqueue_struct *ksuspend_usb_wq #ifdef CONFIG_USB_SUSPEND static int usb_autosuspend_delay = 2; /* Default delay value, * in seconds */ -module_param_named(autosuspend, usb_autosuspend_delay, uint, 0644); +module_param_named(autosuspend, usb_autosuspend_delay, int, 0644); MODULE_PARM_DESC(autosuspend, "default autosuspend delay"); #else --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -394,7 +394,7 @@ struct usb_device { struct delayed_work autosuspend; /* for delayed autosuspends */ struct mutex pm_mutex; /* protects PM operations */ - unsigned autosuspend_delay; /* in jiffies */ + int autosuspend_delay; /* in jiffies */ unsigned auto_pm:1; /* autosuspend/resume in progress */ unsigned do_remote_wakeup:1; /* remote wakeup should be enabled */