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EHCI: fix criterion for resuming the root hub

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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>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alan Stern 2012-04-17 15:24:15 -04:00 committed by Greg Kroah-Hartman
parent 749541d19e
commit dc75ce9d92
1 changed files with 1 additions and 1 deletions
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2
drivers/usb/host/ehci-hcd.c
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@ -910,7 +910,7 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd)
pcd_status = status;
/* resume root hub? */
if (!(cmd & CMD_RUN))
if (ehci->rh_state == EHCI_RH_SUSPENDED)
usb_hcd_resume_root_hub(hcd);
/* get per-port change detect bits */