Re: [REGRESSION][BISECTED] 5.5-rc suspend/resume failure caused by patch a4f55d8b8c14 ("usb: hub: Check device descriptor before resusciation")

[Paul Zimmerman]

Hi Alan,

On 1/23/20 8:50 AM, Alan Stern wrote:
> On Wed, 22 Jan 2020, Paul Zimmerman wrote:
>
> > > Still, since there was no real connection change at the port, there's
> > > no reason to call hub_port_connect_change() here.  Let's see if the
> > > patch below fixes your problem.
> > >
> > > Alan Stern
> > >
> > >
> > >
> > > Index: usb-devel/drivers/usb/core/hub.c
> > > ===================================================================
> > > --- usb-devel.orig/drivers/usb/core/hub.c
> > > +++ usb-devel/drivers/usb/core/hub.c
> > > @@ -1216,11 +1216,6 @@ static void hub_activate(struct usb_hub
> > >   #ifdef CONFIG_PM
> > >   			udev->reset_resume = 1;
> > >   #endif
> > > -			/* Don't set the change_bits when the device
> > > -			 * was powered off.
> > > -			 */
> > > -			if (test_bit(port1, hub->power_bits))
> > > -				set_bit(port1, hub->change_bits);
> > >   
> > >   		} else {
> > >   			/* The power session is gone; tell hub_wq */
> >
> > I can confirm this fixes the issue for me, I did a couple dozen
> > suspend/resume cycles without seeing a failure.
> >
> > I see the code you removed was added by Lan Tianyu in commit
> > ad493e5e5805 ("usb: add usb port auto power off mechanism"). I
>
> No, not really.  The set_bit() call was added by me in a much earlier
> commit (8808f00c7adf, merged in 2008).  Lan Tianyu merely added the
> "if" test, so that set_bit() doesn't always get called.  Now with this
> change, set_bit() never gets called.
>
> > wonder if your patch would break that? I don't know what that is
> > or how to test it.
>
> While some code review by people who are familiar with this material
> wouldn't hurt, I don't think you need to worry about any additional
> testing.
>
> > In any case:
> > Tested-by: Paul Zimmerman <pauldzim@xxxxxxxxx>
>
> Thank you.  I'll submit the patch soon.
>
> Alan Stern

Ping? Unfortunately 5.5 was released with this regression, do you plan
to submit this patch soon?

--
Paul