Regression from patch 'tty: hvc: hvc_poll() break hv read loop'

[Leon Romanovsky]

On Wed, Sep 05, 2018 at 01:51:56PM +1000, Nicholas Piggin wrote:
> On Tue, 4 Sep 2018 15:16:35 -0600
> Jason Gunthorpe <jgg at mellanox.com> wrote:
>
> > On Wed, Sep 05, 2018 at 07:15:29AM +1000, Nicholas Piggin wrote:
> > > On Tue, 4 Sep 2018 11:48:08 -0600
> > > Jason Gunthorpe <jgg at mellanox.com> wrote:
> > >
> > > > Hi Nicholas,
> > > >
> > > > I am testing 4.19-rc2 and I see bad behavior with my qemu hvc0
> > > > console..
> > > >
> > > > Running interactive with qemu (qemu-2.11.2-1.fc28) on the console
> > > > providing hvc0, using options like:
> > > >
> > > >         -nographic
> > > >         -chardev stdio,id=stdio,mux=on,signal=off
> > > >         -mon chardev=stdio
> > > > 	-device isa-serial,chardev=stdio
> > > >         -device virtio-serial-pci
> > > > 	-device virtconsole,chardev=stdio
> > > >
> > > > I see the hvc0 console hang regularly, ie doing something like 'up
> > > > arrow' in bash causes the hvc0 console to hang. Prior kernels worked
> > > > OK.
> > > >
> > > > Any ideas? I'm not familiar with this code.. Thanks!
> > >
> > > Yes I have had another report, I'm working on a fix. Sorry it has taken
> > > a while and thank you for the report.
> >
> > Okay, let me know when you have a fix and I will be able to test it
> > for you!
>
> Can you try this?

It worked for me, so it will work for Jason too (we have same setup).

Tested-by: Leon Romanovsky <leonro at mellanox.com>

Thanks