From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alan Stern , Ming Lei Subject: [ 17/26] USB: EHCI: fix timer bug affecting port resume Date: Thu, 7 Feb 2013 16:57:45 -0800 Message-Id: <20130208004630.246079296@linuxfoundation.org> In-Reply-To: <20130208004627.258272404@linuxfoundation.org> References: <20130208004627.258272404@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alan Stern 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 --- 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; }