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Alan Stern authored
High-speed USB connections revert back to full-speed signalling when the device goes into suspend. This takes several milliseconds, and during that time it's not possible to tell reliably whether the device has been disconnected. On some platforms, the Wake-On-Disconnect circuitry gets confused during this intermediate state. It generates a false wakeup signal, which can prevent the controller from going to sleep. To avoid this problem, this patch adds a 5-ms delay to the ehci_bus_suspend() routine if any ports have to switch over to full-speed signalling. (Actually, the delay was already present for devices using a particular kind of PHY power management; the patch merely causes the delay to be used more widely.) Signed-off-by:
Alan Stern <stern@rowland.harvard.edu> Reviewed-by:
Peter Chen <Peter.Chen@freescale.com> CC: <stable@vger.kernel.org> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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