USB: HWA: fix device probe failure

This patch fixes a race condition that caused the HWA_HC interface probe
function to occasionally fail.  The HWA_HC would attempt to register
itself with the HWA_RC by searching for a uwb_rc class device with the
same parent device ptr.  If the probe function for the HWA_RC interface
had yet to run, the uwb_rc class device would not have been created
causing the look up to fail and the HWA_HC probe function to return an
error causing the device to be unusable.

The fix is for the HWA to delay registering with the HWA_RC until
receiving the command from userspace to start the wireless channel.  It
is the responsibility of userspace to ensure that the uwb_rc class
device has been created before starting the HWA channel.

Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 2 insertions, 7 deletions

diff --git a/drivers/usb/wusbcore/wusbhc.c b/drivers/usb/wusbcore/wusbhc.c
index e712af3e46c2..742c607d1fa3 100644
--- a/drivers/usb/wusbcore/wusbhc.c
+++ b/drivers/usb/wusbcore/wusbhc.c
@@ -325,13 +325,7 @@ int wusbhc_b_create(struct wusbhc *wusbhc)
 		goto error_create_attr_group;
 	}
 
-	result = wusbhc_pal_register(wusbhc);
-	if (result < 0)
-		goto error_pal_register;
 	return 0;
-
-error_pal_register:
-	sysfs_remove_group(wusbhc_kobj(wusbhc), &wusbhc_attr_group);
 error_create_attr_group:
 	return result;
 }
@@ -457,7 +451,8 @@ EXPORT_SYMBOL_GPL(wusbhc_giveback_urb);
  */
 void wusbhc_reset_all(struct wusbhc *wusbhc)
 {
-	uwb_rc_reset_all(wusbhc->uwb_rc);
+	if (wusbhc->uwb_rc)
+		uwb_rc_reset_all(wusbhc->uwb_rc);
 }
 EXPORT_SYMBOL_GPL(wusbhc_reset_all);