On Wed, Sep 21, 2016 at 7:07 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> On Wed, 21 Sep 2016, Greg KH wrote:
>
> > On Wed, Sep 21, 2016 at 11:25:37AM -0400, Alan Stern wrote:
> > > A warning message that was recently added to the PM core has alerted
> > > us to a potential problem in usb-storage. Although the USB interface
> > > is in the runtime active state when the probe routine starts, until
> > > the runtime-PM usage count is incremented nothing forces it to remain
> > > active. The increment doesn't happen until after scsi_add_host() is
> > > called, and that call causes the interface to go into runtime suspend.
> > >
> > > Although this hasn't caused anything to go wrong for anyone, as far as
> > > I know, it still is a bug.
> > >
> > > To prevent this from happening, move the existing call to
> > > usb_autopm_get_interface_no_resume() up from its current position to
> > > before scsi_add_host() is called.
> > >
> > > Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
> > > Reported-by: Carsten Mattner <carstenmattner@xxxxxxxxx>
> > > Tested-by: Carsten Mattner <carstenmattner@xxxxxxxxx>
> > > CC: <stable@xxxxxxxxxxxxxxx>
> >
> > It's a bit late for 4.8 for this, can we wait for 4.9-rc1?
> >
> > This doesn't apply to my usb-next branch, so things have changed in this
> > area, did they solve the issue already?
>
> Heh -- I _thought_ this issue seemed familiar. :-)
>
> Yes, it has already been fixed by commit a094760b9a77 ("usb: storage:
> fix runtime pm issue in usb_stor_probe2") by Heiner Kallweit. I even
> Acked his patch, but I didn't remember it.
>
> So Carsten, there's your answer. The commit will be part of 4.9-rc1,
> unless Greg shoehorns it into 4.8.
Looks reasonable to add to 4.8, but I'm not the maintainer,
so it's not my responsibility or call to make. Greg knows best.
> But if it doesn't get into 4.8 then it should be marked for
> 4.8.stable, to prevent those new warning messages from
> alarming people.
Thanks everyone, especially Alan!
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