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From:   Chen-Yu Tsai <wenst@chromium.org>
Date:   Tue, 28 Sep 2021 15:53:14 +0800
Message-ID: <CAGXv+5G16fZWyyFDHTeaqJG02cYhVm20u47ZXJb+HdHmFc8HSw@mail.gmail.com>
Subject: Re: [PATCH] media: videobuf2: always set buffer vb2 pointer
To:     Sergey Senozhatsky <senozhatsky@chromium.org>
Cc:     Tomasz Figa <tfiga@chromium.org>,
        Hans Verkuil <hverkuil-cisco@xs4all.nl>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Ricardo Ribalda <ribalda@chromium.org>,
        Linux Media Mailing List <linux-media@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Tue, Sep 28, 2021 at 2:24 PM Chen-Yu Tsai <wenst@chromium.org> wrote:
>
> On Tue, Sep 28, 2021 at 2:16 PM Sergey Senozhatsky
> <senozhatsky@chromium.org> wrote:
> >
> > We need to always link allocated vb2_dc_buf back to vb2_buffer because
> > we dereference vb2 in prepare() and finish() callbacks.
> >
> > Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
>
> This fixes the breakage from the "videobuf2: support new noncontiguous DMA
> API" series on the RK3399 Scarlet if the ChromeOS patch that changes
> min_buffers_needed to 0 [1] is not applied.
>
> Since there are other in-tree drivers that have min_buffers_needed=0,
> I would recommend getting some more testing.

Seems I had a stale kernel when testing the min_buffers_needed=0 case.

Everythings works now.

Tested-by: Chen-Yu Tsai <wenst@chromium.org>