usb: Check if port status is equal to RxDetect
authorGavin Guo <gavin.guo@canonical.com>
Thu, 17 Jul 2014 17:12:13 +0000 (01:12 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 28 Jul 2014 15:08:19 +0000 (08:08 -0700)
commitda8ab612bc64d49d158e754c843b777389feb557
tree18a5eeeb732cb219ef5ca0252a368310f16a9924
parent4250b32591fa333087dbecda0aa079cd88c5a640
usb: Check if port status is equal to RxDetect

commit bb86cf569bbd7ad4dce581a37c7fbd748057e9dc upstream.

When using USB 3.0 pen drive with the [AMD] FCH USB XHCI Controller
[1022:7814], the second hotplugging will experience the USB 3.0 pen
drive is recognized as high-speed device. After bisecting the kernel,
I found the commit number 41e7e056cdc662f704fa9262e5c6e213b4ab45dd
(USB: Allow USB 3.0 ports to be disabled.) causes the bug. After doing
some experiments, the bug can be fixed by avoiding executing the function
hub_usb3_port_disable(). Because the port status with [AMD] FCH USB
XHCI Controlleris [1022:7814] is already in RxDetect
(I tried printing out the port status before setting to Disabled state),
it's reasonable to check the port status before really executing
hub_usb3_port_disable().

Fixes: 41e7e056cdc6 (USB: Allow USB 3.0 ports to be disabled.)
Signed-off-by: Gavin Guo <gavin.guo@canonical.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/core/hub.c