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>
diff --git a/drivers/usb/host/hwa-hc.c b/drivers/usb/host/hwa-hc.c
index 4af750e..483990c 100644
--- a/drivers/usb/host/hwa-hc.c
+++ b/drivers/usb/host/hwa-hc.c
@@ -683,12 +683,9 @@
wa->usb_dev = usb_get_dev(usb_dev); /* bind the USB device */
wa->usb_iface = usb_get_intf(iface);
wusbhc->dev = dev;
- wusbhc->uwb_rc = uwb_rc_get_by_grandpa(iface->dev.parent);
- if (wusbhc->uwb_rc == NULL) {
- result = -ENODEV;
- dev_err(dev, "Cannot get associated UWB Host Controller\n");
- goto error_rc_get;
- }
+ /* defer getting the uwb_rc handle until it is needed since it
+ * may not have been registered by the hwa_rc driver yet. */
+ wusbhc->uwb_rc = NULL;
result = wa_fill_descr(wa); /* Get the device descriptor */
if (result < 0)
goto error_fill_descriptor;
@@ -731,8 +728,6 @@
/* WA Descr fill allocs no resources */
error_security_create:
error_fill_descriptor:
- uwb_rc_put(wusbhc->uwb_rc);
-error_rc_get:
usb_put_intf(iface);
usb_put_dev(usb_dev);
return result;