[PATCH] usb: Disable USB3 LPM at shutdown

[Kai-Heng Feng]

SanDisks USB3 storage may disapper after system reboot:

usb usb2-port3: link state change
xhci_hcd 0000:00:14.0: clear port3 link state change, portsc: 0x2c0
usb usb2-port3: do warm reset, port only
xhci_hcd 0000:00:14.0: xhci_hub_status_data: stopping usb2 port polling
xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x2b0, return 0x2b0
usb usb2-port3: not warm reset yet, waiting 50ms
xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x2f0, return 0x2f0
usb usb2-port3: not warm reset yet, waiting 200ms
..
xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x6802c0, return 0x7002c0
usb usb2-port3: not warm reset yet, waiting 200ms
xhci_hcd 0000:00:14.0: clear port3 reset change, portsc: 0x4802c0
xhci_hcd 0000:00:14.0: clear port3 warm(BH) reset change, portsc: 0x4002c0
xhci_hcd 0000:00:14.0: clear port3 link state change, portsc: 0x2c0
xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x2c0, return 0x2c0
usb usb2-port3: not enabled, trying warm reset again...

This is due to the USB device still cause port change event after xHCI is
shuted down:

xhci_hcd 0000:38:00.0: // Setting command ring address to 0xffffe001
xhci_hcd 0000:38:00.0: xhci_resume: starting usb3 port polling.
xhci_hcd 0000:38:00.0: xhci_hub_status_data: stopping usb4 port polling
xhci_hcd 0000:38:00.0: xhci_hub_status_data: stopping usb3 port polling
xhci_hcd 0000:38:00.0: hcd_pci_runtime_resume: 0
xhci_hcd 0000:38:00.0: xhci_shutdown: stopping usb3 port polling.
xhci_hcd 0000:38:00.0: // Halt the HC
xhci_hcd 0000:38:00.0: xhci_shutdown completed - status = 1
xhci_hcd 0000:00:14.0: xhci_shutdown: stopping usb1 port polling.
xhci_hcd 0000:00:14.0: // Halt the HC
xhci_hcd 0000:00:14.0: xhci_shutdown completed - status = 1
xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x1203, return 0x203
xhci_hcd 0000:00:14.0: set port reset, actual port 2-3 status  = 0x1311
xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x201203, return 0x100203
xhci_hcd 0000:00:14.0: clear port3 reset change, portsc: 0x1203
xhci_hcd 0000:00:14.0: clear port3 warm(BH) reset change, portsc: 0x1203
xhci_hcd 0000:00:14.0: clear port3 link state change, portsc: 0x1203
xhci_hcd 0000:00:14.0: clear port3 connect change, portsc: 0x1203
xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x1203, return 0x203
usb 2-3: device not accepting address 2, error -108
xhci_hcd 0000:00:14.0: xHCI dying or halted, can't queue_command
xhci_hcd 0000:00:14.0: Set port 2-3 link state, portsc: 0x1203, write 0x11261
xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x1263, return 0x263
xhci_hcd 0000:00:14.0: set port reset, actual port 2-3 status  = 0x1271
xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x12b1, return 0x2b1
usb usb2-port3: not reset yet, waiting 60ms
ACPI: PM: Preparing to enter system sleep state S5
xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x12f1, return 0x2f1
usb usb2-port3: not reset yet, waiting 200ms
reboot: Restarting system

The port change event is caused by LPM transition, so disabling LPM at shutdown
to make sure the device is in U0 for warmboot.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
---
 drivers/usb/core/port.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index c628c1abc907..c50266d7ce9d 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -418,8 +418,10 @@ static void usb_port_shutdown(struct device *dev)
 {
 	struct usb_port *port_dev = to_usb_port(dev);
 
-	if (port_dev->child)
+	if (port_dev->child) {
 		usb_disable_usb2_hardware_lpm(port_dev->child);
+		usb_unlocked_disable_lpm(port_dev->child);
+	}
 }
 
 static const struct dev_pm_ops usb_port_pm_ops = {
-- 
2.34.1