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Commit b01b03f3 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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USB: add new routine for checking port-resume type 



This patch (as1070) creates a new subroutine to check whether a device
can be resumed.  This code is needed even when CONFIG_USB_SUSPEND
isn't set, because devices do suspend themselves when the root hub
(and hence the entire bus) is suspended, and power sessions can get
lost during a system sleep even without individual port suspends.

The patch also fixes a loose end in USB-Persist reset-resume handling.
When a low- or full-speed device is attached to an EHCI's companion
controller, the port handoff during resume will cause the companion
port's connect-status-change feature to be set.  If that flag isn't
cleared, the port-reset code will think it indicates that the device
has been unplugged and the reset-resume will fail.

Signed-off-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent bd2c7845

drivers/usb/core/hub.c

+63 −26
Original line number Diff line number Diff line
@@ -1821,6 +1821,45 @@ static int hub_port_reset(struct usb_hub *hub, int port1, 


#ifdef	CONFIG_PM



#define MASK_BITS	(USB_PORT_STAT_POWER | USB_PORT_STAT_CONNECTION | \

				USB_PORT_STAT_SUSPEND)

#define WANT_BITS	(USB_PORT_STAT_POWER | USB_PORT_STAT_CONNECTION)



/* Determine whether the device on a port is ready for a normal resume,

 * is ready for a reset-resume, or should be disconnected.

 */

static int check_port_resume_type(struct usb_device *udev,

		struct usb_hub *hub, int port1,

		int status, unsigned portchange, unsigned portstatus)

{

	/* Is the device still present? */

	if (status || (portstatus & MASK_BITS) != WANT_BITS) {

		if (status >= 0)

			status = -ENODEV;

	}



	/* Can't do a normal resume if the port isn't enabled */

	else if (!(portstatus & USB_PORT_STAT_ENABLE) && !udev->reset_resume)

		status = -ENODEV;



	if (status) {

		dev_dbg(hub->intfdev,

				"port %d status %04x.%04x after resume, %d\n",

				port1, portchange, portstatus, status);

	} else if (udev->reset_resume) {



		/* Late port handoff can set status-change bits */

		if (portchange & USB_PORT_STAT_C_CONNECTION)

			clear_port_feature(hub->hdev, port1,

					USB_PORT_FEAT_C_CONNECTION);

		if (portchange & USB_PORT_STAT_C_ENABLE)

			clear_port_feature(hub->hdev, port1,

					USB_PORT_FEAT_C_ENABLE);

	}



	return status;

}



#ifdef	CONFIG_USB_SUSPEND



/*
@@ -2025,7 +2064,6 @@ int usb_port_resume(struct usb_device *udev) 
	int		port1 = udev->portnum;

	int		status;

	u16		portchange, portstatus;

	unsigned	mask_flags, want_flags;



	/* Skip the initial Clear-Suspend step for a remote wakeup */

	status = hub_port_status(hub, port1, &portstatus, &portchange);
@@ -2054,35 +2092,23 @@ int usb_port_resume(struct usb_device *udev) 
		 */

		status = hub_port_status(hub, port1, &portstatus, &portchange);



 SuspendCleared:

		if (udev->reset_resume)

			want_flags = USB_PORT_STAT_POWER

					| USB_PORT_STAT_CONNECTION;

		else

			want_flags = USB_PORT_STAT_POWER

					| USB_PORT_STAT_CONNECTION

					| USB_PORT_STAT_ENABLE;

		mask_flags = want_flags | USB_PORT_STAT_SUSPEND;

		/* TRSMRCY = 10 msec */

		msleep(10);

	}



		if (status < 0 || (portstatus & mask_flags) != want_flags) {

			dev_dbg(hub->intfdev,

				"port %d status %04x.%04x after resume, %d\n",

				port1, portchange, portstatus, status);

			if (status >= 0)

				status = -ENODEV;

		} else {

 SuspendCleared:

	if (status == 0) {

		if (portchange & USB_PORT_STAT_C_SUSPEND)

			clear_port_feature(hub->hdev, port1,

					USB_PORT_FEAT_C_SUSPEND);

			/* TRSMRCY = 10 msec */

			msleep(10);

		}

	}



	clear_bit(port1, hub->busy_bits);

	if (!hub->hdev->parent && !hub->busy_bits[0])

		usb_enable_root_hub_irq(hub->hdev->bus);



	status = check_port_resume_type(udev,

			hub, port1, status, portchange, portstatus);

	if (status == 0)

		status = finish_port_resume(udev);

	if (status < 0) {
@@ -2115,12 +2141,23 @@ int usb_port_suspend(struct usb_device *udev) 
	return 0;

}



/* However we may need to do a reset-resume */



int usb_port_resume(struct usb_device *udev)

{

	int status = 0;

	struct usb_hub	*hub = hdev_to_hub(udev->parent);

	int		port1 = udev->portnum;

	int		status;

	u16		portchange, portstatus;



	/* However we may need to do a reset-resume */

	if (udev->reset_resume) {

	status = hub_port_status(hub, port1, &portstatus, &portchange);

	status = check_port_resume_type(udev,

			hub, port1, status, portchange, portstatus);



	if (status) {

		dev_dbg(&udev->dev, "can't resume, status %d\n", status);

		hub_port_logical_disconnect(hub, port1);

	} else if (udev->reset_resume) {

		dev_dbg(&udev->dev, "reset-resume\n");

		status = usb_reset_device(udev);

	}