On Mon, 13 Jan 2014, Sarah Sharp wrote: > On Mon, Jan 13, 2014 at 02:56:57PM -0800, Sarah Sharp wrote: > > I haven't looked at this too closely, but what happens if: > > - the USB 2.0 roothub is registered > > - userspace immediately sets autosuspend_delay to zero and > > pm_qos_no_port_poweroff to zero > > - usb_acpi_find_device changes the connect_type to something other than > > unknown > > - before usb_acpi_check_port_peer() is called, the port is suspended > > Or that call finishes, but no peer port is set yet, because the USB 3.0 > roothub isn't registered yet. The USB 2.0 bus can be suspended before > the USB 3.0 bus has finished registering, as I've seen from this thread: > > http://marc.info/?l=linux-usb&m=138914518219334&w=2 It's always possible for xhci-hcd to prevent the USB-2 root hub from being suspended by calling pm_runtime_get_noresume. The corresponding _put can be done after the USB-3 root hub has been registered. 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
