Commit 0aa2832d authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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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: default avatarAlan Stern <stern@rowland.harvard.edu>
CC: Peter Chen <peter.chen@freescale.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e9e88fb7

drivers/usb/core/hub.c

+21 −6
Original line number Diff line number Diff line
@@ -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);
@@ -2993,9 +3006,11 @@ 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);

		if (really_suspend) {

			udev->port_is_suspended = 1;

			msleep(10);

		}

	}



	/*

	 * Check whether current status meets the requirement of

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