linux-kernel - Re: [PATCH 0/2] Improve V4L2 M2M job scheduler

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Message-ID: <CAAFQd5CS3ZdUikoPgiHAJTfGScWY7Nbqd2Kc=gnTm2P=JTKkbQ@mail.gmail.com>
Date:   Tue, 22 Aug 2023 16:59:45 +0900
From:   Tomasz Figa <tfiga@...omium.org>
To:     Hans Verkuil <hverkuil@...all.nl>
Cc:     Hsia-Jun Li <randy.li@...aptics.com>, linux-media@...r.kernel.org,
        ayaka@...lik.info, hans.verkuil@...co.com, mchehab@...nel.org,
        laurent.pinchart@...asonboard.com, hiroh@...omium.org,
        linux-kernel@...r.kernel.org, nicolas@...fresne.ca
Subject: Re: [PATCH 0/2] Improve V4L2 M2M job scheduler

On Fri, Aug 18, 2023 at 11:45 PM Hans Verkuil <hverkuil@...all.nl> wrote:
>
> On 04/07/2023 06:00, Hsia-Jun Li wrote:
> > From: "Hsia-Jun(Randy) Li" <randy.li@...aptics.com>
> >
> > The first patch is an old patch, I resend it again.
> > I want to make the work thats parses the bitstream
> > to extract the sequence information or video resolution
> > as a part of V4L2 schedule. Such a work would also
> > consume the device's resources likes remote CPU
> > time.
> >
> > Although reuse a flag which no current driver may
> > not be a good idea. I could add a new flag for that
> > if people like that.
> >
> > The second is a patch offering a generic solution
> > for tracking buffers which have been pushed to
> > hardware(or firmware). It didn't record which buffer
> > that hardware(firmware) still holds for future
> > decoding(likes the reference buffer), while it
> > has been sent to the user(dequeue). We may need
> > a flag for this work.
>
> I am dropping this series from patchwork: clearly this generated
> a lot of discussion, and I think that needs to come to a conclusion.
>
> BTW, I believe that at minimum the codec-specific parts in
> v4l2-mem2mem.c should be split off in their own source (v4l2-m2m-codec.c?).

I like the idea. This way we could possibly evolve the framework more
towards the codec helpers, reusing as much code as possible, but also
keeping the basic implementation simple.

>
> I agree with Tomasz that mem2mem.c was originally for simple m2m devices,
> and adding all sorts of codec specific code to that source doesn't make
> it easier to follow.
>
> Regards,
>
>         Hans
>
> >
> > Hsia-Jun(Randy) Li (1):
> >   media: v4l2-mem2mem: add a list for buf used by hw
> >
> > Randy Li (1):
> >   media: v4l2-mem2mem: allow device run without buf
> >
> >  drivers/media/v4l2-core/v4l2-mem2mem.c | 30 +++++++++++++++++---------
> >  include/media/v4l2-mem2mem.h           | 10 ++++++++-
> >  2 files changed, 29 insertions(+), 11 deletions(-)
> >
>