usb: Fail a get config when the port is powered off.
Alan Stern pointed out that a USB port could potentially get powered off
when the attached USB device is in the middle of enumerating, due to
race conditions:
http://marc.info/?l=linux-usb&m=134130616707548&w=2
If that happens, we need to ensure the enumeration fails. If a call to
usb_get_descriptor() fails for a reason other than a Stall, return an
error. That should handle the case where the port is powered off.
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index f4bdd0c..7199adc 100644
--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -702,6 +702,8 @@
if (result < 0) {
dev_err(ddev, "unable to read config index %d "
"descriptor/%s: %d\n", cfgno, "start", result);
+ if (result != -EPIPE)
+ goto err;
dev_err(ddev, "chopping to %d config(s)\n", cfgno);
dev->descriptor.bNumConfigurations = cfgno;
break;