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authorThomas Pugliese <thomas.pugliese@gmail.com>2013-06-24 23:26:35 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-06-25 03:20:43 +0400
commita899575191ba85a71401f2c8f36bec7b14487043 (patch)
tree74070049b20ec44cf625db68ac62751e4b33cab0 /drivers/usb/wusbcore/mmc.c
parent6e6581e0a94758a4e69fab82407d39312eeff5c4 (diff)
downloadlinux-a899575191ba85a71401f2c8f36bec7b14487043.tar.xz
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>
Diffstat (limited to 'drivers/usb/wusbcore/mmc.c')
-rw-r--r--drivers/usb/wusbcore/mmc.c27
1 files changed, 27 insertions, 0 deletions
diff --git a/drivers/usb/wusbcore/mmc.c b/drivers/usb/wusbcore/mmc.c
index 021467f86d9e..b71760c8d3ad 100644
--- a/drivers/usb/wusbcore/mmc.c
+++ b/drivers/usb/wusbcore/mmc.c
@@ -195,6 +195,7 @@ int wusbhc_start(struct wusbhc *wusbhc)
struct device *dev = wusbhc->dev;
WARN_ON(wusbhc->wuie_host_info != NULL);
+ BUG_ON(wusbhc->uwb_rc == NULL);
result = wusbhc_rsv_establish(wusbhc);
if (result < 0) {
@@ -276,12 +277,38 @@ int wusbhc_chid_set(struct wusbhc *wusbhc, const struct wusb_ckhdid *chid)
}
wusbhc->chid = *chid;
}
+
+ /* register with UWB if we haven't already since we are about to start
+ the radio. */
+ if ((chid) && (wusbhc->uwb_rc == NULL)) {
+ wusbhc->uwb_rc = uwb_rc_get_by_grandpa(wusbhc->dev->parent);
+ if (wusbhc->uwb_rc == NULL) {
+ result = -ENODEV;
+ dev_err(wusbhc->dev, "Cannot get associated UWB Host Controller\n");
+ goto error_rc_get;
+ }
+
+ result = wusbhc_pal_register(wusbhc);
+ if (result < 0) {
+ dev_err(wusbhc->dev, "Cannot register as a UWB PAL\n");
+ goto error_pal_register;
+ }
+ }
mutex_unlock(&wusbhc->mutex);
if (chid)
result = uwb_radio_start(&wusbhc->pal);
else
uwb_radio_stop(&wusbhc->pal);
+
+ return result;
+
+error_pal_register:
+ uwb_rc_put(wusbhc->uwb_rc);
+ wusbhc->uwb_rc = NULL;
+error_rc_get:
+ mutex_unlock(&wusbhc->mutex);
+
return result;
}
EXPORT_SYMBOL_GPL(wusbhc_chid_set);