[PATCH v7 11/11] media: hantro: Support NV12 on the G2 core

[Ezequiel Garcia]

On Wed, 20 Oct 2021 at 12:04, Jernej Škrabec <jernej.skrabec at gmail.com> wrote:
>
> Dne sreda, 20. oktober 2021 ob 13:06:59 CEST je Ezequiel Garcia napisal(a):
> > Hi Jernej,
> >
> > On Tue, 19 Oct 2021 at 13:38, Jernej Škrabec <jernej.skrabec at gmail.com>
> wrote:
> > >
> > > Hi Andrzej!
> > >
> > > Dne petek, 15. oktober 2021 ob 19:19:47 CEST je Andrzej Pietrasiewicz
> > > napisal(a):
> > > > Hi Jernej,
> > > >
> > > > W dniu 14.10.2021 o 19:42, Jernej Škrabec pisze:
> > > > > Hi Andrzej!
> > > > >
> > > > > Dne sreda, 29. september 2021 ob 18:04:39 CEST je Andrzej
> Pietrasiewicz
> > > > > napisal(a):
> > > > >> The G2 decoder block produces NV12 4x4 tiled format (NV12_4L4).
> > > > >> Enable the G2 post-processor block, in order to produce regular NV12.
> > > > >>
> > > > >> The logic in hantro_postproc.c is leveraged to take care of
> allocating
> > > > >> the extra buffers and configure the post-processor, which is
> > > > >> significantly simpler than the one on the G1.
> > > > >
> > > > > Quick summary of discussion on LibreELEC Slack:
> > > > > When using NV12 format on Allwinner H6 variant of G2 (needs some
> driver
> > > > > changes), I get frames out of order. If I use native NV12 tiled
> format,
> > > frames
> > > > > are ordered correctly.
> > > > >
> > > > > Currently I'm not sure if this is issue with my changes or is this
> general
> > > > > issue.
> > > > >
> > > > > I would be grateful if anyone can test frame order with and without
> > > > > postprocessing enabled on imx8. Take some dynamic video with a lot of
> > > short
> > > > > scenes. It's pretty obvious when frames are out of order.
> > > > >
> > > >
> > > > I checked on imx8 and cannot observe any such artifacts.
> > >
> > > I finally found the issue. As you mentioned on Slack, register write order
> once
> > > already affected decoding. Well, it's the case again. I made hacky test and
> > > moved postproc enable call after output buffers are set and it worked. So,
> this
> > > is actually core quirk which is obviously fixed in newer variants.
> > >
> >
> > Ugh, good catch.
> >
> > What happens if you move all the calls to HANTRO_PP_REG_WRITE_S
> > (HANTRO_PP_REG_WRITE does a relaxed write)?
> >
> > Or what happens if the HANTRO_PP_REG_WRITE(vpu, out_luma_base, dst_dma)
> > is moved to be done after all the other registers?
>
> Those two macros aren't used on G2. Andrzej introduced new postproc helpers
> for G2.
>

Ah, so the issue is specific on the G2 post-processor.

> This commit solves issue for H6:
> https://github.com/jernejsk/linux-1/commit/
> a783a977c0843bb4b555dc9d0b5d64915cd219e7
>

Right, but see this comment:

    /* Turn on pipeline mode. Must be done first. */
    HANTRO_PP_REG_WRITE_S(vpu, pipeline_en, 0x1);

I have vague recollection of why we have that comment,
but I'm reluctant to move post-proc enable to the end.
(or at least not do it on G1?).

> >
> > > This makes this series with minor adaptations completely working on H6. I
> see
> > > no reason not to merge whole series.
> > >
> >
> > Do you have plans to submit your H6 work on top of this?
>
> Of course, why would I work on this otherwise? :) But before I do that, I have
> to clean up and split one commit, which adapts VP9 G2 code for H6 variant.
>

OK, sounds good.

> If you're interested in changes, take a look here:
> https://github.com/jernejsk/linux-1/commits/vp9
>

Will take a look.

Thanks,
Ezequiel