This is a note to let you know that I've just added the patch titled
Subject: USB: add usb_autopm_get_interface_burst()
to my gregkh-2.6 tree. Its filename is
usb-add-usb_autopm_get_interface_burst.patch
This tree can be found at
http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/patches/
>From [EMAIL PROTECTED] Fri Jul 6 11:21:32 2007
From: Alan Stern <[EMAIL PROTECTED]>
Date: Fri, 6 Jul 2007 14:21:26 -0400 (EDT)
Subject: USB: add usb_autopm_get_interface_burst()
To: Greg KH <[EMAIL PROTECTED]>
Cc: USB development list <linux-usb-devel@lists.sourceforge.net>
Message-ID: <[EMAIL PROTECTED]>
This patch (as929) adds usb_autopm_get_interface_burst() to the
autosuspend programming interface. It is intended for situations
where I/O events occur in bursts of activity; it reduces overhead by
not cancelling the device's autosuspend timer.
Signed-off-by: Alan Stern <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
---
drivers/usb/core/driver.c | 50 +++++++++++++++++++++++++++++++++++++---------
include/linux/usb.h | 1
2 files changed, 42 insertions(+), 9 deletions(-)
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -1126,6 +1126,7 @@ static int usb_suspend_both(struct usb_d
/**
* usb_resume_both - resume a USB device and its interfaces
* @udev: the usb_device to resume
+ * @burst: flag for burst-mode operation (don't disable the suspend timer)
*
* This is the central routine for resuming USB devices. It calls the
* the resume method for @udev and then calls the resume methods for all
@@ -1136,6 +1137,13 @@ static int usb_suspend_both(struct usb_d
* tree and assuring that @udev will be able to resume. If the parent is
* unable to resume successfully, the routine fails.
*
+ * If @burst is set then @udev's autosuspend timer isn't cancelled. This
+ * helps avoid timer overhead in situations where bursts of I/O requests
+ * occur during a short period of time. If the timer expires later while
+ * @udev is still busy, nothing will happen and the timer won't be restarted.
+ * If the timer expires after @udev has become idle again, it will either
+ * reschedule itself or perform an autosuspend as usual.
+ *
* The resume method calls are subject to mutual exclusion under control
* of @udev's pm_mutex. Many of these calls are also under the protection
* of @udev's device lock (including all requests originating outside the
@@ -1151,14 +1159,15 @@ static int usb_suspend_both(struct usb_d
*
* This routine can run only in process context.
*/
-static int usb_resume_both(struct usb_device *udev)
+static int usb_resume_both(struct usb_device *udev, int burst)
{
int status = 0;
int i;
struct usb_interface *intf;
struct usb_device *parent = udev->parent;
- cancel_delayed_work(&udev->autosuspend);
+ if (!burst)
+ cancel_delayed_work(&udev->autosuspend);
if (udev->state == USB_STATE_NOTATTACHED) {
status = -ENODEV;
goto done;
@@ -1233,7 +1242,7 @@ static int usb_autopm_do_device(struct u
WARN_ON(udev->pm_usage_cnt < 0);
if (inc_usage_cnt >= 0 && udev->pm_usage_cnt > 0) {
if (udev->state == USB_STATE_SUSPENDED)
- status = usb_resume_both(udev);
+ status = usb_resume_both(udev, 0);
if (status != 0)
udev->pm_usage_cnt -= inc_usage_cnt;
else if (inc_usage_cnt)
@@ -1338,7 +1347,7 @@ int usb_autoresume_device(struct usb_dev
* its device's autosuspend state.
*/
static int usb_autopm_do_interface(struct usb_interface *intf,
- int inc_usage_cnt)
+ int inc_usage_cnt, int burst)
{
struct usb_device *udev = interface_to_usbdev(intf);
int status = 0;
@@ -1351,7 +1360,7 @@ static int usb_autopm_do_interface(struc
intf->pm_usage_cnt += inc_usage_cnt;
if (inc_usage_cnt >= 0 && intf->pm_usage_cnt > 0) {
if (udev->state == USB_STATE_SUSPENDED)
- status = usb_resume_both(udev);
+ status = usb_resume_both(udev, burst);
if (status != 0)
intf->pm_usage_cnt -= inc_usage_cnt;
else if (inc_usage_cnt)
@@ -1401,7 +1410,7 @@ void usb_autopm_put_interface(struct usb
{
int status;
- status = usb_autopm_do_interface(intf, -1);
+ status = usb_autopm_do_interface(intf, -1, 0);
dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
__FUNCTION__, status, intf->pm_usage_cnt);
}
@@ -1445,7 +1454,7 @@ int usb_autopm_get_interface(struct usb_
{
int status;
- status = usb_autopm_do_interface(intf, 1);
+ status = usb_autopm_do_interface(intf, 1, 0);
dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
__FUNCTION__, status, intf->pm_usage_cnt);
return status;
@@ -1453,6 +1462,29 @@ int usb_autopm_get_interface(struct usb_
EXPORT_SYMBOL_GPL(usb_autopm_get_interface);
/**
+ * usb_autopm_get_interface_burst - increment a USB interface's PM-usage
counter for burst-mode operation
+ * @intf: the usb_interface whose counter should be incremented
+ *
+ * This routine does almost exactly the same thing as
+ * usb_autopm_get_interface() above. The only difference is that it
+ * doesn't disable the device's autosuspend timer, so there's less
+ * overhead when the routine is called over and over again for a burst
+ * of I/O.
+ *
+ * This routine can run only in process context.
+ */
+int usb_autopm_get_interface_burst(struct usb_interface *intf)
+{
+ int status;
+
+ status = usb_autopm_do_interface(intf, 1, 1);
+ dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
+ __FUNCTION__, status, intf->pm_usage_cnt);
+ return status;
+}
+EXPORT_SYMBOL_GPL(usb_autopm_get_interface_burst);
+
+/**
* usb_autopm_set_interface - set a USB interface's autosuspend state
* @intf: the usb_interface whose state should be set
*
@@ -1467,7 +1499,7 @@ int usb_autopm_set_interface(struct usb_
{
int status;
- status = usb_autopm_do_interface(intf, 0);
+ status = usb_autopm_do_interface(intf, 0, 0);
dev_vdbg(&intf->dev, "%s: status %d cnt %d\n",
__FUNCTION__, status, intf->pm_usage_cnt);
return status;
@@ -1524,7 +1556,7 @@ int usb_external_resume_device(struct us
usb_pm_lock(udev);
udev->auto_pm = 0;
- status = usb_resume_both(udev);
+ status = usb_resume_both(udev, 0);
udev->last_busy = jiffies;
usb_pm_unlock(udev);
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -442,6 +442,7 @@ extern struct usb_device *usb_find_devic
#ifdef CONFIG_USB_SUSPEND
extern int usb_autopm_set_interface(struct usb_interface *intf);
extern int usb_autopm_get_interface(struct usb_interface *intf);
+extern int usb_autopm_get_interface_burst(struct usb_interface *intf);
extern void usb_autopm_put_interface(struct usb_interface *intf);
static inline void usb_autopm_enable(struct usb_interface *intf)
Patches currently in gregkh-2.6 which might be from [EMAIL PROTECTED] are
driver/sysfs-implement-sysfs_find_dirent-and-sysfs_get_dirent.patch
driver/sysfs-use-sysfs_mutex-to-protect-the-sysfs_dirent-tree.patch
driver/pm-remove-pm_parent-from-struct-dev_pm_info.patch
driver/pm-remove-saved_state-from-struct-dev_pm_info.patch
driver/pm-simplify-suspend_device.patch
driver/sysfs-consolidate-sysfs-spinlocks.patch
driver/sysfs-implement-sysfs_flag_removed-flag.patch
driver/sysfs-implement-sysfs_get_dentry.patch
driver/sysfs-make-directory-dentries-and-inodes-reclaimable.patch
driver/sysfs-make-kobj-point-to-sysfs_dirent-instead-of-dentry.patch
driver/sysfs-make-sysfs_drop_dentry-access-inodes-using-ilookup.patch
driver/sysfs-move-sysfs_drop_dentry-to-dir.c-and-make-it-static.patch
driver/sysfs-rename-sysfs_dirent-s_type-to-s_flags-and-make-room-for-flags.patch
driver/sysfs-restructure-add-remove-paths-and-fix-inode-update.patch
driver/pm-remove-prev_state-from-struct-dev_pm_info.patch
driver/pm-do-not-check-parent-state-in-suspend-and-resume-core-code.patch
driver/pm-remove-power_state.event-checks-from-suspend-core-code.patch
usb/usb-add-usb-persist-facility.patch
usb/usb-core-hub.c-prevent-re-enumeration-on-hnp.patch
usb/usb-add-reset_resume-device-quirk.patch
usb/usb-don-t-unsuspend-for-a-new-connection.patch
usb/usb-implement-pm-freeze-and-prethaw.patch
usb/usb-add-usb_autopm_get_interface_burst.patch
usb/usb-disable-file_storage-usb_config_att_wakeup.patch
usb/usb-interface-pm-state.patch
usb/usb-make-hub-driver-s-release-more-robust.patch
usb/usb-move-bus_suspend-and-bus_resume-method-calls.patch
usb/usb-remove-locktree-routine-from-the-hub-driver.patch
usb/usb-remove-references-to-dev.power.power_state.patch
usb/usb-make-device-reset-stop-retrying-after-disconnect.patch
usb/usb-add-power-persist-device-attribute.patch
usb/usb-add-reset_resume-method.patch
usb/usb-remove-__usb_port_suspend.patch
usb/usb-remove-excess-code-from-hub.c.patch
usb/usb-separate-root-and-non-root-suspend-resume.patch
usb/usb-unify-reset_resume-and-normal-resume.patch
usb/usb-add-usb_device_and_interface_info-for-device-matching.patch
usb/usb-ehci-fix-handover-for-designated-full-speed-ports.patch
usb/usb-ehci-ohci-handover-changes.patch
usb/usb-option-fix-usage-of-urb-status-abuse.patch
usb/usb-prevent-char-device-open-deregister-race.patch
usb/usb-rework-c-style-comments.patch
usb/usb-usb-storage-use-kthread_stop-for-the-control-thread.patch
usb/usb-handle-bogus-low-speed-bulk-endpoints.patch
usb/usb-don-t-resume-root-hub-if-the-controller-is-suspended.patch
usb/usb-fix-off-by-1-error-in-the-scatter-gather-library.patch
usb/usb-fix-up-full-speed-binterval-values-in-high-speed-interrupt-descriptor.patch
usb/usb-remove-usages-of-dev-power.power_state.patch
usb/usb-drivers-usb-storage-unusual_devs.h-whitespace-cleanup.patch
usb/usb-storage-implement-autosuspend.patch
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