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/usb.c b/drivers/usb/core/usb.c
index 25d0c61..cd8fb44 100644
--- a/drivers/usb/core/usb.c
+++ b/drivers/usb/core/usb.c
@@ -396,6 +396,7 @@
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);