[ 178/221] USB: hub: handle claim of enabled remote wakeup after reset

Greg Kroah-Hartman
2013-01-16T00:02:29Z

From: Oliver Neukum <oliver@neukum.org>

commit 07e72b95f5038cc82304b9a4a2eb7f9fc391ea68 upstream.

Some touchscreens have buggy firmware which claims
remote wakeup to be enabled after a reset. They nevertheless
crash if the feature is cleared by the host.
Add a check for reset resume before checking for
an enabled remote wakeup feature. On compliant
devices the feature must be cleared after a reset anyway.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/usb/core/hub.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2960,7 +2960,7 @@ int usb_port_suspend(struct usb_device *
static int finish_port_resume(struct usb_device *udev)
{
int status = 0;
- u16 devstatus;
+ u16 devstatus = 0;

/* caller owns the udev device lock */
dev_dbg(&udev->dev, "%s\n",
@@ -3005,7 +3005,13 @@ static int finish_port_resume(struct usb
if (status) {
dev_dbg(&udev->dev, "gone after usb resume? status %d\n",
status);
- } else if (udev->actconfig) {
+ /*
+ * There are a few quirky devices which violate the standard
+ * by claiming to have remote wakeup enabled after a reset,
+ * which crash if the feature is cleared, hence check for
+ * udev->reset_resume
+ */
+ } else if (udev->actconfig && !udev->reset_resume) {
le16_to_cpus(&devstatus);
if (devstatus & (1 << USB_DEVICE_REMOTE_WAKEUP)) {
status = usb_control_msg(udev,