> This patch (as1532) fixes a mistake in the USB suspend code. When the
> system is going to sleep, we should ignore errors in powering down USB
> devices, because they don't really matter. The devices will go to low
> power anyway when the entire USB bus gets suspended (except for
> SuperSpeed devices; maybe they will need special treatment later).
>
> However we should not ignore errors in suspending root hubs,
> especially if the error indicates that the suspend raced with a wakeup
> request. Doing so might leave the bus powered on while the system was
> supposed to be asleep, or it might cause the suspend of the root hub's
> parent controller device to fail, or it might cause a wakeup request
> to be ignored.
>
> The patch fixes the problem by ignoring errors only when the device in
> question is not a root hub.
>
> Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
> Reported-by: Chen Peter <B29397@xxxxxxxxxxxxx>
> CC: <stable@xxxxxxxxxxxxxxx>
>
> ---
>
> drivers/usb/core/driver.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> Index: usb-3.3/drivers/usb/core/driver.c
> ===================================================================
> --- usb-3.3.orig/drivers/usb/core/driver.c
> +++ usb-3.3/drivers/usb/core/driver.c
> @@ -1189,8 +1189,13 @@ static int usb_suspend_both(struct usb_d
> if (status == 0) {
> status = usb_suspend_device(udev, msg);
>
> - /* Again, ignore errors during system sleep transitions */
> - if (!PMSG_IS_AUTO(msg))
> + /*
> + * Ignore errors from non-root-hub devices during
> + * system sleep transitions. For the most part,
> + * these devices should go to low power anyway when
> + * the entire bus is suspended.
> + */
> + if (udev->parent && !PMSG_IS_AUTO(msg))
> status = 0;
> }
>
>
Tested-by: Chen Peter <peter.chen@xxxxxxxxxxxxx>
This patch is tested at Freescale MX6 Sabrelite board with v3.0.15 kernel.
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