On Wed, 23 Jan 2013, Peter Chen wrote: > On Tue, Jan 22, 2013 at 03:08:27PM -0500, Alan Stern wrote: > > Lei: > > > > It turns out that your patch setting the autosuspend delay for hubs to > > 0 causes problems for root hubs. They need a delay of at least 30 ms. > > > > When a child device sends a remote wakeup request, the root hub > > generates an interrupt. The HCD's interrupt handler sees what happened > > and requests a runtime resume for the root hub. > Does below code at kick_khubd will avoid hub going to autosuspend? > usb_autopm_get_interface_no_resume( > to_usb_interface(hub->intfdev)); It does -- but only until hub_events() runs. hub_events() calls usb_autopm_put_interface(). 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
