USB: Disable LPM while the device is unconfigured.

The USB 3.0 Set/Clear Feature U1/U2 Enable cannot be sent to a device in
the Default or Addressed state.  It can only be sent to a configured
device.  Change the USB core to initialize the LPM disable count to 1
(disabled), which reflects this limitation.

Change usb_set_configuration() to ensure that if the device is
unconfigured on entry, usb_lpm_disable() is not called.  This avoids
sending the Clear Feature U1/U2 when the device is in the Addressed
state.  When usb_set_configuration() exits with a successfully installed
configuration, usb_lpm_enable() will be called.

Once the new configuration is installed, make sure
usb_set_configuration() only calls usb_enable_lpm() if the device moved
to the Configured state.  If we have unconfigured the device by sending
it a Set Configuration for config 0, don't enable LPM.

This commit should be backported to kernels as old as 3.5, that contain
the commit 8306095fd2c1100e8244c09bf560f97aca5a311d "USB: Disable USB
3.0 LPM in critical sections."

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 8b9d669..3723904 100644 (file)
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1792,14 +1792,15 @@ free_interfaces:
         * installed, so that the xHCI driver can recalculate the U1/U2
         * timeouts.
         */
-       if (usb_disable_lpm(dev)) {
+       if (dev->actconfig && usb_disable_lpm(dev)) {
                dev_err(&dev->dev, "%s Failed to disable LPM\n.", __func__);
                mutex_unlock(hcd->bandwidth_mutex);
                return -ENOMEM;
        }
        ret = usb_hcd_alloc_bandwidth(dev, cp, NULL, NULL);
        if (ret < 0) {
-               usb_enable_lpm(dev);
+               if (dev->actconfig)
+                       usb_enable_lpm(dev);
                mutex_unlock(hcd->bandwidth_mutex);
                usb_autosuspend_device(dev);
                goto free_interfaces;
@@ -1819,7 +1820,7 @@ free_interfaces:
        if (!cp) {
                usb_set_device_state(dev, USB_STATE_ADDRESS);
                usb_hcd_alloc_bandwidth(dev, NULL, NULL, NULL);
-               usb_enable_lpm(dev);
+               /* Leave LPM disabled while the device is unconfigured. */
                mutex_unlock(hcd->bandwidth_mutex);
                usb_autosuspend_device(dev);
                goto free_interfaces;

diff --git a/drivers/usb/core/usb.c b/drivers/usb/core/usb.c
index 25d0c61..cd8fb44 100644 (file)
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -396,6 +396,7 @@ struct usb_device *usb_alloc_dev(struct usb_device *parent,
        dev->dev.dma_mask = bus->controller->dma_mask;
        set_dev_node(&dev->dev, dev_to_node(bus->controller));
        dev->state = USB_STATE_ATTACHED;
+       dev->lpm_disable_count = 1;
        atomic_set(&dev->urbnum, 0);
 
        INIT_LIST_HEAD(&dev->ep0.urb_list);