USB: Disable USB2 LPM at shutdown

The QCA Rome USB Bluetooth controller has several issues once LPM gets
enabled:
- Fails to get enumerated in coldboot. [1]
- Drains more power (~ 0.2W) when the system is in S5. [2]
- Disappears after a warmboot. [2]

The issue happens because the device lingers at LPM L1 in S5, so device
can't get enumerated even after a reboot.

Disable LPM at shutdown to solve the issue.

[1] https://bugs.launchpad.net/bugs/1757218
[2] https://patchwork.kernel.org/patch/10607097/

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Link: https://lore.kernel.org/r/20190805142412.23965-1-kai.heng.feng@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index 1a06a4b5fbb14d592b6da8ed2cab8ebd123eb851..bbbb35fa639fa43e6666eebfdb86c909595f6cf8 100644 (file)
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -285,6 +285,14 @@ static int usb_port_runtime_suspend(struct device *dev)
 }
 #endif
 
+static void usb_port_shutdown(struct device *dev)
+{
+       struct usb_port *port_dev = to_usb_port(dev);
+
+       if (port_dev->child)
+               usb_disable_usb2_hardware_lpm(port_dev->child);
+}
+
 static const struct dev_pm_ops usb_port_pm_ops = {
 #ifdef CONFIG_PM
        .runtime_suspend =      usb_port_runtime_suspend,
@@ -301,6 +309,7 @@ struct device_type usb_port_device_type = {
 static struct device_driver usb_port_driver = {
        .name = "usb",
        .owner = THIS_MODULE,
+       .shutdown = usb_port_shutdown,
 };
 
 static int link_peers(struct usb_port *left, struct usb_port *right)