On Tue, 1 Oct 2013, yoma sophian wrote: > 2013/9/30 Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>: > > On Mon, 30 Sep 2013, yoma sophian wrote: > > > >> hi all: > >> We are trying to make usb hibernate work on our embedded system. > >> below are configs we enable for system power management: > > > > Do you mean "hibernate" or "sleep"? > it is a little complex to describe what we can. > 1. DDR power is still keep alive, so data is ok (suspend) > 2. But cpu/usb is power off (hibernate) > > > so I intend to replace suspend function with hibernate ones. > such that ehci power off/on can follow hibernate rule. The main difference between suspend and hibernate is that in suspend, the memory contents remain intact. In hibernation, the memory contents are written out to disk (and then read back in from disk the next time the system starts up). Therefore it seems like your case is most similar to suspend. > >> When we use "echo mem > /sys/power/state" , we didn't see any function > > > > "mem" is a kind of sleep, not a kind of hibernation. > But I don't see any usb sleep funciton called from log What messages do you expect to see? And what version of the kernel are you using? Alan Stern -- 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
