On Wed, 28 Nov 2012, Rafael J. Wysocki wrote:
> On Wednesday, November 28, 2012 12:44:02 PM Alan Stern wrote:
> > On Sat, 17 Nov 2012, Lan Tianyu wrote:
> >
> > > This patch is to expose usb port's pm qos flags(pm_qos_no_power_off,
> > > pm_qos_remote_wakeup) to user space. User can set pm_qos_no_power_off
> > > flag to prohibit the port from being power off.
> >
> > Do we really need this? The user already can prevent the port from
> > being powered off by writing "on" to the power/control attribute.
>
> But that will prevent whoever is the parent of the port and its parent etc.
> from suspending.
To make this scheme work, we will have to set the parent's
ignore_children flag. Otherwise a hub with unconnected ports would
never suspend. Tianyu, you need to call
pm_runtime_suspend_ignore_children(&intf->dev, true);
near the end of hub_probe() and
pm_runtime_suspend_ignore_children(&intf->dev, false);
near the end of hub_disconnect(). These should be added to patch 7/10.
Alan Stern
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