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authorGavin Guo <gavin.guo@canonical.com>2014-07-18 01:12:13 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-07-17 17:14:01 -0700
commitbb86cf569bbd7ad4dce581a37c7fbd748057e9dc (patch)
treee060189ded706c0dfd10d5946fd758d76b71a5a9 /drivers/usb/core
parent953c66469735aed8d2ada639a72b150f01dae605 (diff)
downloadlinux-stericsson-bb86cf569bbd7ad4dce581a37c7fbd748057e9dc.tar.gz
usb: Check if port status is equal to RxDetect
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> Cc: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/core')
-rw-r--r--drivers/usb/core/hub.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 21b99b4b4082..0e950ad8cb25 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -889,6 +889,25 @@ static int hub_usb3_port_disable(struct usb_hub *hub, int port1)
if (!hub_is_superspeed(hub->hdev))
return -EINVAL;
+ ret = hub_port_status(hub, port1, &portstatus, &portchange);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * USB controller Advanced Micro Devices, Inc. [AMD] FCH USB XHCI
+ * Controller [1022:7814] will have spurious result making the following
+ * usb 3.0 device hotplugging route to the 2.0 root hub and recognized
+ * as high-speed device if we set the usb 3.0 port link state to
+ * Disabled. Since it's already in USB_SS_PORT_LS_RX_DETECT state, we
+ * check the state here to avoid the bug.
+ */
+ if ((portstatus & USB_PORT_STAT_LINK_STATE) ==
+ USB_SS_PORT_LS_RX_DETECT) {
+ dev_dbg(&hub->ports[port1 - 1]->dev,
+ "Not disabling port; link state is RxDetect\n");
+ return ret;
+ }
+
ret = hub_set_port_link_state(hub, port1, USB_SS_PORT_LS_SS_DISABLED);
if (ret)
return ret;