Re: [PATCH 1/1] driver core: disable device's runtime pm during shutdown

From: Rafael J. Wysocki
Date: Tue Nov 15 2011 - 18:13:30 EST


On Tuesday, November 15, 2011, Greg KH wrote:
> On Mon, Nov 14, 2011 at 11:27:37PM +0100, Rafael J. Wysocki wrote:
> > On Monday, November 14, 2011, Peter Chen wrote:
> > > There may be an issue when the user issue "reboot/shutdown" command, then
> > > the device has shut down its hardware, after that, this runtime-pm featured
> > > device's driver will probably be scheduled to do its suspend routine,
> > > and at its suspend routine, it may access hardware, but the device has
> > > already shutdown physically, then the system hang may be occurred.
> > >
> > > I ran out this issue using an auto-suspend supported USB devices, like
> > > 3G modem, keyboard. The usb runtime suspend routine may be scheduled
> > > after the usb controller has been shut down, and the usb runtime suspend
> > > routine will try to suspend its roothub(controller), it will access
> > > register, then the system hang occurs as the controller is shutdown.
> > > Signed-off-by: Peter Chen <peter.chen@xxxxxxxxxxxxx>
> >
> > Greg, do you want me to take this one?
>
> Please do:
> Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

Done, thanks!

Rafael
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