From: Andiry Xu <andiry.xu@xxxxxxxxx> USB2 LPM is disabled when device begin to suspend and enabled after device is resumed. That's because USB spec does not define the transition from U1/U2 state to U3 state. If usb_port_suspend() fails, usb_port_resume() is never called, and USB2 LPM is disabled in this situation. Enable USB2 LPM if port suspend fails. This patch should be backported to kernels as old as 3.2, that contain the commit 65580b4321eb36f16ae8b5987bfa1bb948fc5112 "xHCI: set USB2 hardware LPM". Signed-off-by: Andiry Xu <andiry.xu@xxxxxxxxx> Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx --- drivers/usb/core/hub.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index ec6c97d..c8e0704 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -2499,6 +2499,10 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg) NULL, 0, USB_CTRL_SET_TIMEOUT); + /* Try to enable USB2 hardware LPM again */ + if (udev->usb2_hw_lpm_capable == 1) + usb_set_usb2_hardware_lpm(udev, 1); + /* System sleep transitions should never fail */ if (!PMSG_IS_AUTO(msg)) status = 0; -- 1.7.9 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
