From: Alan Stern <stern@rowland.harvard.edu>
Date: Fri, 25 Jan 2013 22:17:43 +0000 (-0500)
Subject: USB: EHCI: fix timer bug affecting port resume
X-Git-Tag: v3.8-rc7~13^2~10
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ee74290b7853db9d5fd64db70e5c175241c59fba;p=pandora-kernel.git

USB: EHCI: fix timer bug affecting port resume

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>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

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