From ee49fb5dc89d34f1794ac9362fa97c1a640f7ddd Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Wed, 22 Nov 2006 16:55:54 -0500 Subject: [PATCH] USB: keep count of unsuspended children This patch (as818b) simplifies autosuspend processing by keeping track of the number of unsuspended children of each USB hub. This will permit us to avoid a good deal of unnecessary work all the time; we will no longer have to create a bunch of workqueue entries to carry out autosuspend requests, only to have them fail because one of the hub's children isn't suspended. The basic idea is simple. There already is a usage counter in the usb_device structure for preventing autosuspends. The patch just increments that counter for every unsuspended child. There's only one tricky part: When a device disconnects we need to remember whether it was suspended at the time (leave the counter alone) or not (decrement the counter). Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/driver.c | 34 +++++++++++++++++++++++----------- drivers/usb/core/hub.c | 14 ++++++++++++++ include/linux/usb.h | 1 + 3 files changed, 38 insertions(+), 11 deletions(-) diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c index 40c1bf0..0fa15bd 100644 --- a/drivers/usb/core/driver.c +++ b/drivers/usb/core/driver.c @@ -1048,7 +1048,7 @@ int usb_suspend_both(struct usb_device *udev, pm_message_t msg) /* If the suspend succeeded, propagate it up the tree */ } else if (parent) - usb_autosuspend_device(parent, 0); + usb_autosuspend_device(parent, 1); // dev_dbg(&udev->dev, "%s: status %d\n", __FUNCTION__, status); return status; @@ -1096,9 +1096,25 @@ int usb_resume_both(struct usb_device *udev) /* Propagate the resume up the tree, if necessary */ if (udev->state == USB_STATE_SUSPENDED) { if (parent) { - usb_pm_lock(parent); - parent->auto_pm = 1; - status = usb_resume_both(parent); + status = usb_autoresume_device(parent, 1); + if (status == 0) { + status = usb_resume_device(udev); + if (status) { + usb_autosuspend_device(parent, 1); + + /* It's possible usb_resume_device() + * failed after the port was + * unsuspended, causing udev to be + * logically disconnected. We don't + * want usb_disconnect() to autosuspend + * the parent again, so tell it that + * udev disconnected while still + * suspended. */ + if (udev->state == + USB_STATE_NOTATTACHED) + udev->discon_suspended = 1; + } + } } else { /* We can't progagate beyond the USB subsystem, @@ -1107,11 +1123,9 @@ int usb_resume_both(struct usb_device *udev) if (udev->dev.parent->power.power_state.event != PM_EVENT_ON) status = -EHOSTUNREACH; - } - if (status == 0) - status = usb_resume_device(udev); - if (parent) - usb_pm_unlock(parent); + else + status = usb_resume_device(udev); + } } else { /* Needed only for setting udev->dev.power.power_state.event @@ -1119,8 +1133,6 @@ int usb_resume_both(struct usb_device *udev) status = usb_resume_device(udev); } - /* Now the parent won't suspend until we are finished */ - if (status == 0 && udev->actconfig) { for (i = 0; i < udev->actconfig->desc.bNumInterfaces; i++) { intf = udev->actconfig->interface[i]; diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 46df5e6..e46d38b 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -1039,6 +1039,8 @@ static void recursively_mark_NOTATTACHED(struct usb_device *udev) if (udev->children[i]) recursively_mark_NOTATTACHED(udev->children[i]); } + if (udev->state == USB_STATE_SUSPENDED) + udev->discon_suspended = 1; udev->state = USB_STATE_NOTATTACHED; } @@ -1228,6 +1230,14 @@ void usb_disconnect(struct usb_device **pdev) *pdev = NULL; spin_unlock_irq(&device_state_lock); + /* Decrement the parent's count of unsuspended children */ + if (udev->parent) { + usb_pm_lock(udev); + if (!udev->discon_suspended) + usb_autosuspend_device(udev->parent, 1); + usb_pm_unlock(udev); + } + put_device(&udev->dev); } @@ -1356,6 +1366,10 @@ static int __usb_new_device(void *void_data) goto fail; } + /* Increment the parent's count of unsuspended children */ + if (udev->parent) + usb_autoresume_device(udev->parent, 1); + exit: module_put(THIS_MODULE); return err; diff --git a/include/linux/usb.h b/include/linux/usb.h index 5634a2d..0cd73ed 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -362,6 +362,7 @@ struct usb_device { u8 portnum; /* Parent port number (origin 1) */ u8 level; /* Number of USB hub ancestors */ + unsigned discon_suspended:1; /* Disconnected while suspended */ unsigned have_langid:1; /* whether string_langid is valid */ int string_langid; /* language ID for strings */ -- 2.7.4