Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 17/26] USB: EHCI: fix timer bug affecting port resume | Date | Thu, 7 Feb 2013 16:57:45 -0800 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Alan Stern <stern@rowland.harvard.edu>
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 <stern@rowland.harvard.edu> Reported-and-tested-by: Norbert Preining <preining@logic.at> Tested-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/usb/host/ehci-hub.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- 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 *hc 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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