If suspend callback fails in system sleep context, usb core will ignore the failure and let system sleep go ahead further, so this patch comments on the case and requires that serial->type->suspend() MUST return 0 in system sleep context. Cc: Johan Hovold <jhovold@xxxxxxxxx> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxxxxx> --- drivers/usb/serial/usb-serial.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c index a19ed74..16eb02b 100644 --- a/drivers/usb/serial/usb-serial.c +++ b/drivers/usb/serial/usb-serial.c @@ -1140,6 +1140,11 @@ int usb_serial_suspend(struct usb_interface *intf, pm_message_t message) serial->suspending = 1; + /* + * serial->type->suspend() MUST return 0 in system sleep context, + * otherwise, the resume callback has to recover device from + * previous suspend failure. + */ if (serial->type->suspend) { r = serial->type->suspend(serial, message); if (r < 0) { -- 1.7.9.5 -- 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