[RFC PATCH v4] tty: pl011: Avoid spuriously stuck-off interrupts

[Andrew Jones]

On Thu, Apr 26, 2018 at 01:11:41PM +0100, Peter Maydell wrote:
> On 26 April 2018 at 11:54, Dave Martin <Dave.Martin at arm.com> wrote:
> > This is an update to a previous RFC v3 [1], to fix a problem observed by
> > the qemu community that causes serial input to hang when booting a
> > simulated system with data already queued in the UART FIFO [2].
> >
> > RFC v3 did not solve the problem by itself, due to the problem being
> > triggered again in pl011_enable_interrupts() after working around it
> > in pl011_hwinit().  See the updated commit message in the patch for
> > details.
> >
> > This patch is intended to supersede the previous RFCs, so please test
> > _without_ RFC v2 (or 3) applied.
> >
> > If you can, please:
> >
> >  a) Check that you can still reproduce the bug on mainline without this
> >     patch.
> >
> >  b) Check whether this patch fixes the problem.
> 
> Adding back to the CC list the people who might be able to do
> this testing...
> Link to v4 patch:
> https://patchwork.kernel.org/patch/10365551/
>

Tested-by: Andrew Jones <drjones at redhat.com>

And
 
Reviewed-by: Andrew Jones <drjones at redhat.com>

as this patch is consistent with what I expected was needed back
when I reported the issue[*]. I was just too dense to realize
that we didn't need to "reset" the FIFO, but rather just drain it.

Thanks,
drew

[*] https://lkml.org/lkml/2016/8/1/247