This patch takes care of the race condition between the Function Wake
Device Notification and the auto-suspend timeout for this situation:
Roothub
| (U3)
hub A
| (U3)
hub B
| (U3)
device C
When device C signals a resume, the xHCI driver will set the wakeup_bits
for the roothub port that hub A is attached to. However, since USB 3.0
hubs do not set a link state change bit on device-initiated resume, hub
A will not indicate a port event when polled. Without this patch, khubd
will notice the wakeup-bits are set for the roothub port, it will resume
hub A, and then it will poll the events bits for hub A and notice that
nothing has changed. Then it will be suspended after 2 seconds.
When we notice that a port has resumed on a USB 3.0 hub, and the device
attached to that port is a hub, set the wakeup_bits for all the child
hub's ports. That means we'll poll the status for all ports on hub B
to find the one that woke up, but that's better than missing a device
remote wakeup.
Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
---
drivers/usb/core/hub.c | 25 +++++++++++++++++++------
1 files changed, 19 insertions(+), 6 deletions(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 657d6ad..b0c923d 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3474,12 +3474,13 @@ done:
/* Returns 1 if there was a remote wakeup and a connect status change. */
static int hub_handle_remote_wakeup(struct usb_hub *hub, unsigned int port,
- u16 portchange)
+ u16 portstatus, u16 portchange)
{
struct usb_device *hdev;
struct usb_device *udev;
+ struct usb_hub *child_hub;
int connect_change = 0;
- int ret;
+ int ret, i;
hdev = hub->hdev;
udev = hdev->children[port-1];
@@ -3489,8 +3490,8 @@ static int hub_handle_remote_wakeup(struct usb_hub *hub, unsigned int port,
clear_port_feature(hdev, port, USB_PORT_FEAT_C_SUSPEND);
} else {
if (!udev || udev->state != USB_STATE_SUSPENDED ||
- !test_and_clear_bit(udev->portnum,
- hub->wakeup_bits))
+ (portstatus & USB_PORT_STAT_LINK_STATE) !=
+ USB_SS_PORT_LS_U0)
return 0;
}
@@ -3499,6 +3500,17 @@ static int hub_handle_remote_wakeup(struct usb_hub *hub, unsigned int port,
msleep(10);
usb_lock_device(udev);
+ /* USB 3.0 hubs don't report suspend changes due to device
+ * remote wakeups, so mark all the children as woken up.
+ */
+ if (hub_is_superspeed(hdev) && udev->maxchild > 0) {
+ child_hub = hdev_to_hub(udev);
+ if (child_hub) {
+ for (i = 1; i < udev->maxchild; i++)
+ set_bit(i, child_hub->wakeup_bits);
+ }
+ kick_khubd(child_hub);
+ }
ret = usb_remote_wakeup(udev);
usb_unlock_device(udev);
if (ret < 0)
@@ -3603,7 +3615,7 @@ static void hub_events(void)
if (test_bit(i, hub->busy_bits))
continue;
connect_change = test_bit(i, hub->change_bits);
- wakeup_change = test_bit(i, hub->wakeup_bits);
+ wakeup_change = test_and_clear_bit(i, hub->wakeup_bits);
if (!test_and_clear_bit(i, hub->event_bits) &&
!connect_change && !wakeup_change)
continue;
@@ -3646,7 +3658,8 @@ static void hub_events(void)
}
}
- if (hub_handle_remote_wakeup(hub, i, portchange))
+ if (hub_handle_remote_wakeup(hub, i,
+ portstatus, portchange))
connect_change = 1;
if (portchange & USB_PORT_STAT_C_OVERCURRENT) {
--
1.7.5.4
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