+From stern@rowland.harvard.edu Tue Jun 10 14:31:37 2008

+From: Linus Torvalds <torvalds@linux-foundation.org>

+Date: Tue, 10 Jun 2008 14:59:43 -0400 (EDT)

+Subject: USB: don't use reset-resume if drivers don't support it

+To: Greg KH <greg@kroah.com>

+Cc: Linus Torvalds <torvalds@linux-foundation.org>, Oliver Neukum <oliver@neukum.org>, Pavel Machek <pavel@suse.cz>, USB list <linux-usb@vger.kernel.org>, Andrew Morton <akpm@linuxfoundation.org>, kernel list <linux-kernel@vger.kernel.org>, "Rafael J. Wysocki" <rjw@sisk.pl>

+Message-ID: <Pine.LNX.4.44L0.0806101454480.3658-100000@iolanthe.rowland.org>

+

+From: Linus Torvalds <torvalds@linux-foundation.org>

+

+This patch tries to identify which devices are able to accept

+reset-resume handling, by checking that there is at least one

+interface driver bound and that all of the drivers have a reset_resume

+method defined. If these conditions don't hold then during resume

+processing, the device is logicall disconnected.

+

+This is only a temporary fix. Later on we will explicitly unbind

+drivers that can't handle reset-resumes.

+

+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

+Signed-off-by: Alan Stern <stern@rowland.harvard.edu>

+Cc: Oliver Neukum <oliver@neukum.org>

+Cc: Pavel Machek <pavel@suse.cz>

+Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

+

+---

+ drivers/usb/core/hub.c | 46 ++++++++++++++++++++++++++++++++++++++++++++--

+ 1 file changed, 44 insertions(+), 2 deletions(-)

+

+--- a/drivers/usb/core/hub.c

++++ b/drivers/usb/core/hub.c

+@@ -644,6 +644,48 @@ static void hub_stop(struct usb_hub *hub

+

+ #ifdef CONFIG_PM

+

++/* Try to identify which devices need USB-PERSIST handling */

++static int persistent_device(struct usb_device *udev)

++{

++ int i;

++ int retval;

++ struct usb_host_config *actconfig;

++

++ /* Explicitly not marked persistent? */

++ if (!udev->persist_enabled)

++ return 0;

++

++ /* No active config? */

++ actconfig = udev->actconfig;

++ if (!actconfig)

++ return 0;

++

++ /* FIXME! We should check whether it's open here or not! */

++

++ /*

++ * Check that all the interface drivers have a

++ * 'reset_resume' entrypoint

++ */

++ retval = 0;

++ for (i = 0; i < actconfig->desc.bNumInterfaces; i++) {

++ struct usb_interface *intf;

++ struct usb_driver *driver;

++

++ intf = actconfig->interface[i];

++ if (!intf->dev.driver)

++ continue;

++ driver = to_usb_driver(intf->dev.driver);

++ if (!driver->reset_resume)

++ return 0;

++ /*

++ * We have at least one driver, and that one

++ * has a reset_resume method.

++ */

++ retval = 1;

++ }

++ return retval;

++}

++

+ static void hub_restart(struct usb_hub *hub, int type)

+ {

+ struct usb_device *hdev = hub->hdev;

+@@ -689,8 +731,8 @@ static void hub_restart(struct usb_hub *

+ * turn off the various status changes to prevent

+ * khubd from disconnecting it later.

+ */

+- if (udev->persist_enabled && status == 0 &&

+- !(portstatus & USB_PORT_STAT_ENABLE)) {

++ if (status == 0 && !(portstatus & USB_PORT_STAT_ENABLE) &&

++ persistent_device(udev)) {

+ if (portchange & USB_PORT_STAT_C_ENABLE)

+ clear_port_feature(hub->hdev, port1,

+ USB_PORT_FEAT_C_ENABLE);