From 42cfa82f8201f91cdb7539a6e15c6ee15eee7f73 Mon Sep 17 00:00:00 2001 From: Gavin Guo Date: Fri, 18 Jul 2014 01:12:13 +0800 Subject: [PATCH] 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 Acked-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hub.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 46efdca96952..63c217053668 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -887,6 +887,25 @@ 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; -- 2.20.1