EHCI: fix criterion for resuming the root hub
authorAlan Stern <stern@rowland.harvard.edu>
Tue, 17 Apr 2012 19:24:15 +0000 (15:24 -0400)
committerBen Hutchings <ben@decadent.org.uk>
Fri, 11 May 2012 12:14:02 +0000 (13:14 +0100)
commit1c09b62a4c42d7049e433458859f1c4e61467693
treecbec80213e6322bb65be4bf125db51f075609fb4
parenta7e8b05866d9ab6b9f01bd56f3c1abe5af2500bb
EHCI: fix criterion for resuming the root hub

commit dc75ce9d929aabeb0843a6b1a4ab320e58ba1597 upstream.

This patch (as1542) changes the criterion ehci-hcd uses to tell when
it needs to resume the controller's root hub.  A resume is needed when
a port status change is detected, obviously, but only if the root hub
is currently suspended.

Right now the driver tests whether the root hub is running, and that
is not the correct test.  In particular, if the controller has died
then the root hub should not be restarted.  In addition, some buggy
hardware occasionally requires the root hub to be running and
sending out SOF packets even while it is nominally supposed to be
suspended.

In the end, the test needs to be changed.  Rather than checking whether
the root hub is currently running, the driver will now check whether
the root hub is currently suspended.  This will yield the correct
behavior in all cases.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Peter Chen <B29397@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
drivers/usb/host/ehci-hcd.c