[PATCH] drm/tve200: Stabilize enable/disable

[Daniel Vetter]

On Tue, Sep 1, 2020 at 7:52 PM Linus Walleij <linus.walleij at linaro.org> wrote:
>
> On Thu, Aug 20, 2020 at 10:32 PM Linus Walleij <linus.walleij at linaro.org> wrote:
>
> > The TVE200 will occasionally print a bunch of lost interrupts
> > and similar dmesg messages, sometimes during boot and sometimes
> > after disabling and coming back to enablement. This is probably
> > because the hardware is left in an unknown state by the boot
> > loader that displays a logo.
> >
> > This can be fixed by bringing the controller into a known state
> > by resetting the controller while enabling it. We retry reset 5
> > times like the vendor driver does. We also put the controller
> > into reset before de-clocking it and clear all interrupts before
> > enabling the vblank IRQ.
> >
> > This makes the video enable/disable/enable cycle rock solid
> > on the D-Link DIR-685. Tested extensively.
> >
> > Cc: stable at vger.kernel.org
> > Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
>
> Would someone have mercy on this patch and review or
> at least ACK it so I can merge it?

Does what it says on the label, looks symmetric, and "do this five
times for luck" is a classic.

Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>

The irq reset looks a bit like maybe separate patch, but *shrug*,
since your description says you're missing interrupts, not that you
have too many. But can't hurt (and maybe if we have spurious ones it
then looks like the next vblank went missing, so makes some sense).

Cheers, Daniel

> I offer any reviews in return, on stuff I understand, such
> as panel drivers.


>
> Best regards,
> Linus Walleij
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch