diff options
authorAlan Stern <>2013-01-25 17:17:43 -0500
committerGreg Kroah-Hartman <>2013-02-11 08:47:19 -0800
commitf4cc7a1602ed1bb673cf86b6ccc10f72e1cfaae4 (patch)
parent18591ae05a4bc4f505ae5a7d6e58962900226443 (diff)
USB: EHCI: fix timer bug affecting port resume
commit ee74290b7853db9d5fd64db70e5c175241c59fba upstream. This patch (as1652) fixes a long-standing bug in ehci-hcd. The driver relies on status polls to know when to stop port-resume signalling. It uses the root-hub status timer to schedule these status polls. But when the driver for the root hub is resumed, the timer is rescheduled to go off immediately -- before the port is ready. When this happens the timer does not get re-enabled, which prevents the port resume from finishing until some other event occurs. The symptom is that when a new device is plugged in, it doesn't get recognized or enumerated until lsusb is run or something else happens. The solution is to re-enable the root-hub status timer after every status poll while a port resume is in progress. This bug hasn't surfaced before now because we never used to try to suspend the root hub in the middle of a port resume (except by coincidence). Signed-off-by: Alan Stern <> Reported-and-tested-by: Norbert Preining <> Tested-by: Ming Lei <> Signed-off-by: Greg Kroah-Hartman <>
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index 38fe0762315..3cb52a93803 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -612,7 +612,11 @@ ehci_hub_status_data (struct usb_hcd *hcd, char *buf)
status = STS_PCD;
- /* FIXME autosuspend idle root hubs */
+ /* If a resume is in progress, make sure it can finish */
+ if (ehci->resuming_ports)
+ mod_timer(&hcd->rh_timer, jiffies + msecs_to_jiffies(25));
spin_unlock_irqrestore (&ehci->lock, flags);
return status ? retval : 0;