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

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>
This commit is contained in:
Linus Torvalds 2008-06-10 14:59:43 -04:00 committed by Greg Kroah-Hartman
parent e6942d633b
commit 5340ba827b
1 changed files with 44 additions and 2 deletions
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46
drivers/usb/core/hub.c
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@ -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 *hub, int type)
* 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);