path: root/drivers/usb/core/hub.c
diff options
authorSarah Sharp <sarah.a.sharp@linux.intel.com>2012-11-14 16:10:49 -0800
committerSarah Sharp <sarah.a.sharp@linux.intel.com>2013-01-03 14:10:22 -0800
commit8b8132bc3d1cc3d4c0687e4d638a482fa920d98a (patch)
tree6a5cda1a519510937e2aa64e74618701250fb439 /drivers/usb/core/hub.c
parent1c7439c61fa6516419c32a9824976334ea969d47 (diff)
USB: Ignore xHCI Reset Device status.
When the USB core finishes reseting a USB device, the xHCI driver sends a Reset Device command to the host. The xHC then updates its internal representation of the USB device to the 'Default' device state. If the device was already in the Default state, the xHC will complete the command with an error status. If a device needs to be reset several times during enumeration, the second reset will always fail because of the xHCI Reset Device command. This can cause issues during enumeration. For example, usb_reset_and_verify_device calls into hub_port_init in a loop. Say that on the first call into hub_port_init, the device is successfully reset, but doesn't respond to several set address control transfers. Then the port will be disabled, but the udev will remain in tact. usb_reset_and_verify_device will call into hub_port_init again. On the second call into hub_port_init, the device will be reset, and the xHCI driver will issue a Reset Device command. This command will fail (because the device is already in the Default state), and usb_reset_and_verify_device will fail. The port will be disabled, and the device won't be able to enumerate. Fix this by ignoring the return value of the HCD reset_device callback. This commit should be backported to kernels as old as 3.2, that contain the commit 75d7cf72ab9fa01dc70877aa5c68e8ef477229dc "usbcore: refine warm reset logic". Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers/usb/core/hub.c')
1 files changed, 5 insertions, 8 deletions
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 7f8f10ec127..3bc50fc110e 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2565,14 +2565,11 @@ static void hub_port_finish_reset(struct usb_hub *hub, int port1,
msleep(10 + 40);
update_devnum(udev, 0);
hcd = bus_to_hcd(udev->bus);
- if (hcd->driver->reset_device) {
- *status = hcd->driver->reset_device(hcd, udev);
- if (*status < 0) {
- dev_err(&udev->dev, "Cannot reset "
- "HCD device state\n");
- break;
- }
- }
+ /* The xHC may think the device is already reset,
+ * so ignore the status.
+ */
+ if (hcd->driver->reset_device)
+ hcd->driver->reset_device(hcd, udev);