usb: musb: fix enumeration after resume

[Andreas Kemnade <andreas@kemnade.info>]

On Wed, 7 Feb 2018 14:37:00 -0600
Bin Liu <b-liu@ti.com> wrote:

> On Tue, Feb 06, 2018 at 08:00:24PM +0100, Andreas Kemnade wrote:
> > Hi,
> > 
> > On Tue, 6 Feb 2018 12:46:05 -0600
> > Bin Liu <b-liu@ti.com> wrote:
> >   
> > > Hi,
> > > 
> > > On Sat, Jan 27, 2018 at 09:34:03AM +0100, Andreas Kemnade wrote:  
> > > > On dm3730 there are enumeration problems after resume.
> > > > Investigation led to the cause that the MUSB_POWER_SOFTCONN
> > > > bit is not set. If it was set before suspend (because it
> > > > was enabled via musb_pullup()), it is set in
> > > > musb_restore_context() so the pullup is enabled. But then
> > > > musb_start() is called which overwrites MUSB_POWER and
> > > > therefore disables MUSB_POWER_SOFTCONN, so no pullup is
> > > > enabled and the device is not enumerated.    
> > >  
> > > Do you see the issue with the v4.15?
> > >   
> > Yes. Tested without other patches. 
> > It was also there in earlier kernels but I had not had motivation enough
> > to debug.  
> 
> Applied to my tree. Thanks.
> 
> > So maybe it deserves a CC: Stable  
> 
> I would prefer it is first tested on each stable tree.
> 
Tested with 4.16-rc1 with and without that patch
The problem still exists and can be fixed by that patch.

Regards,
Andreas