Re: [PATCH v1 5/5] media: venus: update number of bytes used field properly for EOS frames

[Alexandre Courbot <acourbot@chromium.org>]

On Mon, Nov 12, 2018 at 9:20 PM Stanimir Varbanov
<stanimir.varbanov@linaro.org> wrote:
>
> Hi Alex,
>
> On 11/12/18 10:12 AM, Alexandre Courbot wrote:
> > Hi Stan,
> >
> > On Thu, Nov 8, 2018 at 7:16 PM Stanimir Varbanov
> > <stanimir.varbanov@linaro.org> wrote:
> >>
> >> Hi,
> >>
> >> On 9/29/18 3:00 PM, Srinu Gorle wrote:
> >>> - In video decoder session, update number of bytes used for
> >>>   yuv buffers appropriately for EOS buffers.
> >>>
> >>> Signed-off-by: Srinu Gorle <sgorle@codeaurora.org>
> >>> ---
> >>>  drivers/media/platform/qcom/venus/vdec.c | 2 +-
> >>>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> NACK, that was already discussed see:
> >>
> >> https://patchwork.kernel.org/patch/10630411/
> >
> > I believe you are referring to this discussion?
> >
> > https://lkml.org/lkml/2018/10/2/302
> >
> > In this case, with https://patchwork.kernel.org/patch/10630411/
> > applied, I am seeing the troublesome case of having the last (empty)
> > buffer being returned with a payload of obs_sz, which I believe is
> > incorrect. The present patch seems to restore the correct behavior.
>
> Sorry, I thought that this solution was suggested (and tested on Venus
> v4) by you, right?

That's correct. >_< Looks like I overlooked this case.

>
> >
> > An alternative would be to set the payload as follows:
> >
> > vb2_set_plane_payload(vb, 0, bytesused);
> >
> > This works for SDM845, but IIRC we weren't sure that this would
> > display the correct behavior with all firmware versions?
>
> OK if you are still seeing issues I think we can switch to
> vb2_set_plane_payload(vb, 0, bytesused); for all buffers? I.e. not only
> for buffers with flag V4L2_BUF_FLAG_LAST set.

That's the fix I am currently using in my source tree and it indeed
seems to be ok. I also agree it is better than special-casing EOS
buffers. I have sent a patch for this.

Thanks and sorry for the confusion.