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author | Thomas Pugliese <thomas.pugliese@gmail.com> | 2013-06-24 21:26:35 +0200 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-06-25 01:20:43 +0200 |
commit | a899575191ba85a71401f2c8f36bec7b14487043 (patch) | |
tree | 74070049b20ec44cf625db68ac62751e4b33cab0 /drivers/usb/host/hwa-hc.c | |
parent | wusbcore: add entries in Documentation/ABI for new wusbhc sysfs attributes (diff) | |
download | linux-a899575191ba85a71401f2c8f36bec7b14487043.tar.xz linux-a899575191ba85a71401f2c8f36bec7b14487043.zip |
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/host/hwa-hc.c')
-rw-r--r-- | drivers/usb/host/hwa-hc.c | 11 |
1 files changed, 3 insertions, 8 deletions
diff --git a/drivers/usb/host/hwa-hc.c b/drivers/usb/host/hwa-hc.c index 4af750ecfe8f..483990c716aa 100644 --- a/drivers/usb/host/hwa-hc.c +++ b/drivers/usb/host/hwa-hc.c @@ -683,12 +683,9 @@ static int hwahc_create(struct hwahc *hwahc, struct usb_interface *iface) 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 @@ error_wusbhc_create: /* 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; |