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USB: use "global suspend" for system sleep on USB-2 buses 

This patch (as1674) speeds up system sleep transitions by not
suspending each individual device on a USB-1.1 or USB-2 bus.  The
devices will automatically go into suspend when their root hubs are
suspended (i.e., stop sending out Start-Of-Frame packets) -- this is
what the USB spec calls "global suspend".

Since this is what we do already when CONFIG_USB_SUSPEND isn't
enabled, it shouldn't cause any problems.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alan Stern 2013-03-27 16:14:19 -04:00 committed by Greg Kroah-Hartman
parent e9e88fb7bc
commit 0aa2832dd0
1 changed files with 21 additions and 6 deletions
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27
drivers/usb/core/hub.c
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@ -2886,9 +2886,11 @@ static int usb_disable_function_remotewakeup(struct usb_device *udev)
* Linux (2.6) currently has NO mechanisms to initiate that: no khubd
* timer, no SRP, no requests through sysfs.
*
* If CONFIG_USB_SUSPEND isn't enabled, devices only really suspend when
* the root hub for their bus goes into global suspend ... so we don't
* (falsely) update the device power state to say it suspended.
* If CONFIG_USB_SUSPEND isn't enabled, non-SuperSpeed devices really get
* suspended only when their bus goes into global suspend (i.e., the root
* hub is suspended). Nevertheless, we change @udev->state to
* USB_STATE_SUSPENDED as this is the device's "logical" state. The actual
* upstream port setting is stored in @udev->port_is_suspended.
*
* Returns 0 on success, else negative errno.
*/
@ -2899,6 +2901,7 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
enum pm_qos_flags_status pm_qos_stat;
int port1 = udev->portnum;
int status;
bool really_suspend = true;
/* enable remote wakeup when appropriate; this lets the device
* wake up the upstream hub (including maybe the root hub).
@ -2955,9 +2958,19 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
/* see 7.1.7.6 */
if (hub_is_superspeed(hub->hdev))
status = hub_set_port_link_state(hub, port1, USB_SS_PORT_LS_U3);
else
else if (PMSG_IS_AUTO(msg))
status = set_port_feature(hub->hdev, port1,
USB_PORT_FEAT_SUSPEND);
/*
* For system suspend, we do not need to enable the suspend feature
* on individual USB-2 ports. The devices will automatically go
* into suspend a few ms after the root hub stops sending packets.
* The USB 2.0 spec calls this "global suspend".
*/
else {
really_suspend = false;
status = 0;
}
if (status) {
dev_dbg(hub->intfdev, "can't suspend port %d, status %d\n",
port1, status);
@ -2993,8 +3006,10 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
(PMSG_IS_AUTO(msg) ? "auto-" : ""),
udev->do_remote_wakeup);
usb_set_device_state(udev, USB_STATE_SUSPENDED);
udev->port_is_suspended = 1;
msleep(10);
if (really_suspend) {
udev->port_is_suspended = 1;
msleep(10);
}
}
/*