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
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -1792,14 +1792,15 @@
* 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 @@
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;