[PATCH 08/81] USB: EHCI: fix timer bug affecting port resume
From: Herton Ronaldo Krzesinski
Date: Tue Feb 19 2013 - 13:50:39 EST
18.104.22.168 -stable review patch. If anyone has any objections, please let me know.
From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
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
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Reported-and-tested-by: Norbert Preining <preining@xxxxxxxx>
Tested-by: Ming Lei <ming.lei@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@xxxxxxxxxxxxx>
drivers/usb/host/ehci-hub.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index fc9e7cc..349d3fe 100644
@@ -613,7 +613,11 @@ 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;
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