On Fri, May 07, 2021 at 05:33:28PM +0800, chris.chiu@xxxxxxxxxxxxx wrote:
> From: Chris Chiu <chris.chiu@xxxxxxxxxxxxx>
>
> On the Realtek hub of Dell Dock WD19, 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. However, the hub will fail to activate because the
> PORT_SUSPEND feature of that port is not cleared during resume. All
> devices connecting via the port are lost after resume.
>
> This commit force reset-resume the device connected to the timeout
> but suspended port so that the hub will have chance to clear the
> PORT_SUSPEND feature during resume.
>
> Signed-off-by: Chris Chiu <chris.chiu@xxxxxxxxxxxxx>
> ---
> drivers/usb/core/hub.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index b2bc4b7c4289..18603949a8de 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -3385,6 +3385,21 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
> status = 0;
> }
> if (status) {
> + if (status == -ETIMEDOUT) {
> + u16 portstatus, portchange;
> +
> + status = hub_port_status(hub, port1, &portstatus,
> + &portchange);
Don't reuse status like this. There will be a problem if this line sets
status to 0 but the port isn't actually suspended. Use a different
variable instead.
Alan Stern
> +
> + dev_dbg(&port_dev->dev,
> + "suspend timeout, status %04x\n", portstatus);
> +
> + if (status == 0 && port_is_suspended(hub, portstatus)) {
> + udev->reset_resume = 1;
> + goto err_wakeup;
> + }
> + }
> +
> dev_dbg(&port_dev->dev, "can't suspend, status %d\n", status);
>
> /* Try to enable USB3 LTM again */
> --
> 2.20.1
>
