[PATCH 3.16 183/366] USB: Increment wakeup count on remote wakeup.

Ben Hutchings
2018-10-14T23:37:05Z

From: Ravi Chandra Sadineni <ravisadineni@chromium.org>

commit 83a62c51ba7b3c0bf45150c4eac7aefc6c785e94 upstream.

On chromebooks we depend on wakeup count to identify the wakeup source.
But currently USB devices do not increment the wakeup count when they
trigger the remote wake. This patch addresses the same.

Resume condition is reported differently on USB 2.0 and USB 3.0 devices.

On USB 2.0 devices, a wake capable device, if wake enabled, drives
resume signal to indicate a remote wake (USB 2.0 spec section 7.1.7.7).
The upstream facing port then sets C_PORT_SUSPEND bit and reports a
port change event (USB 2.0 spec section 11.24.2.7.2.3). Thus if a port
has resumed before driving the resume signal from the host and
C_PORT_SUSPEND is set, then the device attached to the given port might
be the reason for the last system wakeup. Increment the wakeup count for
the same.

On USB 3.0 devices, a function may signal that it wants to exit from device
suspend by sending a Function Wake Device Notification to the host (USB3.0
spec section 8.5.6.4) Thus on receiving the Function Wake, increment the
wakeup count.

Signed-off-by: Ravi Chandra Sadineni <ravisadineni@chromium.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/usb/core/hcd.c | 1 +
drivers/usb/core/hub.c | 10 +++++++++-
2 files changed, 10 insertions(+), 1 deletion(-)

--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2293,6 +2293,7 @@ void usb_hcd_resume_root_hub (struct usb

spin_lock_irqsave (&hcd_root_hub_lock, flags);
if (hcd->rh_registered) {
+ pm_wakeup_event(&hcd->self.root_hub->dev, 0);
set_bit(HCD_FLAG_WAKEUP_PENDING, &hcd->flags);
queue_work(pm_wq, &hcd->wakeup_work);
}
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -626,12 +626,17 @@ void usb_wakeup_notification(struct usb_
unsigned int portnum)
{
struct usb_hub *hub;
+ struct usb_port *port_dev;

if (!hdev)
return;

hub = usb_hub_to_struct_hub(hdev);
if (hub) {
+ port_dev = hub->ports[portnum - 1];
+ if (port_dev && port_dev->child)
+ pm_wakeup_event(&port_dev->child->dev, 0);
+
set_bit(portnum, hub->wakeup_bits);
kick_khubd(hub);
}
@@ -3313,8 +3318,11 @@ int usb_port_resume(struct usb_device *u

/* Skip the initial Clear-Suspend step for a remote wakeup */
status = hub_port_status(hub, port1, &portstatus, &portchange);
- if (status == 0 && !port_is_suspended(hub, portstatus))
+ if (status == 0 && !port_is_suspended(hub, portstatus)) {
+ if (portchange & USB_PORT_STAT_C_SUSPEND)
+ pm_wakeup_event(&udev->dev, 0);
goto SuspendCleared;
+ }

/* see 7.1.7.7; affects power usage, but not budgeting */
if (hub_is_superspeed(hub->hdev))