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Commit 9cf65991 authored by Sarah Sharp's avatar Sarah Sharp
Browse files

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 8306095f "USB: Disable USB
3.0 LPM in critical sections."

Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org
parent 6d1d0513

drivers/usb/core/message.c

+4 −3
Original line number Diff line number Diff line
@@ -1792,13 +1792,14 @@ int usb_set_configuration(struct usb_device *dev, int configuration) 
	 * 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) {

		if (dev->actconfig)

			usb_enable_lpm(dev);

		mutex_unlock(hcd->bandwidth_mutex);

		usb_autosuspend_device(dev);
@@ -1819,7 +1820,7 @@ int usb_set_configuration(struct usb_device *dev, int configuration) 
	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;

drivers/usb/core/usb.c

+1 −0
Original line number Diff line number Diff line
@@ -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);