On Fri, 13 Apr 2012, Stephen Warren wrote: > > If you do: > > > > echo auto >/sys/devices/.../power/control > > > > (where the ... gets filled in with the path to the EHCI controller), > > then the controller should automatically get powered down whenever the > > bus does. The bus will get powered down whenever no USB devices are > > plugged in (or the only attached USB devices are things like hubs that > > will themselves get suspended) after a 2-second delay. > > One small issue with the patch: There are two copies of > tegra_ehci_resume(). I assume the second should be renamed > tegra_ehci_runtime_resume(). Whoops! You're right, of course. I'll update my patch. > I've tested the patch, and can unplug a USB device, wait 10 seconds, > then plug it back in, and everything works as expected. > > However, I don't notice /sys/devices/.../power/runtime_status ever > saying anything other than active, and I can't cat autosuspend_delay_ms, > so I assume I'm still not triggering the path you want me to test. I do > have PM_RUNTIME turned on. Any ideas? Do I need some patch to the USB > core to enable this? I tested on next-20120413 plus a few local patches. autosuspend_delay_ms isn't relevant here; the controller should be suspended with no delay as soon as the root hub suspends. No other patches should be needed; it sounds like you're doing everything right. If you enable CONFIG_PM_ADVANCED_DEBUG along with CONFIG_PM_RUNTIME, what do all the other power/runtime_* files show? 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
