[PATCH v4 1/2] USB: Verify the port status when timeout happens during port suspend

From: chris . chiu
Date: Fri May 14 2021 - 00:54:28 EST


From: Chris Chiu <chris.chiu@xxxxxxxxxxxxx>

On the Realtek high-speed Hub(0bda:5487), the port which has wakeup
enabled_descendants will sometimes timeout when setting PORT_SUSPEND
feature. After checking the PORT_SUSPEND bit in wPortStatus, it is
already set which means the port has been suspended. We should treat
it suspended to make sure it will be resumed correctly.

Signed-off-by: Chris Chiu <chris.chiu@xxxxxxxxxxxxx>
---

Changelog:
v4:
- add comment for the timeout handling
- intialize the portstatus and portchange
- revise the commit message to reflect the change
v3:
- create a new goto target for the timeout case instead of
reset_resume
- Revise the commit title/message because reset_resume is not
required.
v2:
- create a new variable to keep the result of hub_port_status
when suspend timeout.

drivers/usb/core/hub.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index b2bc4b7c4289..e739f7b5991a 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3385,6 +3385,26 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
status = 0;
}
if (status) {
+ /* Check if the port has been suspended for the timeout case
+ * to prevent the suspended port from incorrect handling.
+ */
+ if (status == -ETIMEDOUT) {
+ int ret;
+ u16 portstatus, portchange;
+
+ portstatus = portchange = 0;
+ ret = hub_port_status(hub, port1, &portstatus,
+ &portchange);
+
+ dev_dbg(&port_dev->dev,
+ "suspend timeout, status %04x\n", portstatus);
+
+ if (ret == 0 && port_is_suspended(hub, portstatus)) {
+ status = 0;
+ goto suspend_done;
+ }
+ }
+
dev_dbg(&port_dev->dev, "can't suspend, status %d\n", status);

/* Try to enable USB3 LTM again */
@@ -3401,6 +3421,7 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
if (!PMSG_IS_AUTO(msg))
status = 0;
} else {
+ suspend_done:
dev_dbg(&udev->dev, "usb %ssuspend, wakeup %d\n",
(PMSG_IS_AUTO(msg) ? "auto-" : ""),
udev->do_remote_wakeup);
--
2.20.1