AcoSail/kernel_optimize_test
8
0
Fork 0
forked from luck/tmp_suning_uos_patched
Code Pull Requests Activity

USB: change handling of negative autosuspend delays

Browse Source 
This patch (as1327) changes the way negative autosuspend delays
prevent device from autosuspending.  The current code checks for
negative values explicitly in the autosuspend_check() routine.  The
updated code keeps things from getting that far by using
usb_autoresume_device() to increment the usage counter when a negative
delay is set, and by using usb_autosuspend_device() to decrement the
usage counter when a non-negative delay is set.

This complicates the set_autosuspend() attribute method code slightly,
but it will reduce the overall power management overhead.

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 2010-01-08 12:57:02 -05:00 committed by Greg Kroah-Hartman
parent 088f7fec8a
commit 5899f1e020
2 changed files with 27 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/usb/core/quirks.c
View File

@ -103,11 +103,21 @@ void usb_detect_quirks(struct usb_device *udev)
dev_dbg(&udev->dev, "USB quirks for this device: %x\n",
udev->quirks);
#ifdef CONFIG_USB_SUSPEND
/* By default, disable autosuspend for all devices. The hub driver
* will enable it for hubs.
*/
usb_disable_autosuspend(udev);
/* Autosuspend can also be disabled if the initial autosuspend_delay
* is negative.
*/
if (udev->autosuspend_delay < 0)
usb_autoresume_device(udev);
#endif
/* For the present, all devices default to USB-PERSIST enabled */
#if 0 /* was: #ifdef CONFIG_PM */
/* Hubs are automatically enabled for USB-PERSIST */

22
drivers/usb/core/sysfs.c
View File

@ -346,7 +346,8 @@ set_autosuspend(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct usb_device *udev = to_usb_device(dev);
int value;
int value, old_delay;
int rc;
if (sscanf(buf, "%d", &value) != 1 || value >= INT_MAX/HZ ||
value <= - INT_MAX/HZ)
@ -354,13 +355,24 @@ set_autosuspend(struct device *dev, struct device_attribute *attr,
value *= HZ;
usb_lock_device(udev);
old_delay = udev->autosuspend_delay;
udev->autosuspend_delay = value;
if (value >= 0)
usb_try_autosuspend_device(udev);
else {
if (usb_autoresume_device(udev) == 0)
if (old_delay < 0) { /* Autosuspend wasn't allowed */
if (value >= 0)
usb_autosuspend_device(udev);
} else { /* Autosuspend was allowed */
if (value < 0) {
rc = usb_autoresume_device(udev);
if (rc < 0) {
count = rc;
udev->autosuspend_delay = old_delay;
}
} else {
usb_try_autosuspend_device(udev);
}
}
usb_unlock_device(udev);
return count;
}