[PATCH v2] USB: Disable USB2 LPM at shutdown

Kai-Heng Feng
2019-01-24T06:16:57Z

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>
---
v2: Use new LPM helpers.

drivers/usb/core/port.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index 1a06a4b5fbb1..bbbb35fa639f 100644
--- 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)
--
2.17.1