On 04/17/2012 08:56 AM, Alan Stern wrote: > On Mon, 16 Apr 2012, Stephen Warren wrote: > >>>> The EHCI controller's active_kids count stays at 1 all the time. I >>>> assume that's the root USB hub device. Looking in its power/ directory, >>>> I see that even when nothing is plugged in, runtime_status==enabled, >>>> even with no active_kids or runtime_usage: >>> >>> That does indeed sound like a bug. Aha, there's a CONFIG_USB_SUSPEND which I didn't have enabled. Now I see the controller suspending. However, the controller suspends immediately the system boots even if there's a device already connected, and never resumes if there wasn't connected at boot, but one is plugged in later. In this state, I must set tegra-ehci.2/usb3/power/control=on to get anything to work. Forcing just the controller on (tegra-ehci.2/power/control=on) doesn't fix this. After than, I can set tegra-ehci.2/usb3/power/control=auto, and see the root hub (tegra-ehci.2/usb3/power) suspending/resuming as devices are unplugged/plugged. I just can't have tegra-ehci.2/power/control=auto while nothing is plugged in, or the cycle starts again. I assume this a bug in the Tegra EHCI driver's suspend implementation? -- 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
