linux-kernel - Re: [PATCH] media: uvcvideo: Implement V4L2_EVENT_FRAME

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CANiDSCsnrb5a3XTnHRrUjttcV6aAw7yC6RtUApvsK5CBhFGJyQ@mail.gmail.com>
Date:   Mon, 6 Nov 2023 11:51:06 +0100
From:   Ricardo Ribalda <ribalda@...omium.org>
To:     Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        Esker Wong <esker@...omium.org>
Subject: Re: [PATCH] media: uvcvideo: Implement V4L2_EVENT_FRAME_SYNC

Hi Laurent

On Mon, 6 Nov 2023 at 11:42, Laurent Pinchart
<laurent.pinchart@...asonboard.com> wrote:
>
> On Mon, Nov 06, 2023 at 12:39:26PM +0200, Laurent Pinchart wrote:
> > On Fri, Oct 20, 2023 at 06:41:45AM +0000, Ricardo Ribalda wrote:
> > > Add support for the frame_sync event, so user-space can become aware
> > > earlier of new frames.
> > >
> > > Suggested-by: Esker Wong <esker@...omium.org>
> > > Tested-by: Esker Wong <esker@...omium.org>
> > > Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
> > > ---
> > > We have measured a latency of around 30msecs between frame sync
> > > and dqbuf.
> >
> > Not surprising, especially for large resolutions. I'm curious though,
> > what do you use this event for ?

I think Esker is using it to get more accurate power measurements of
the camera stack.

> > It's easy to miss the ++ there when reading the code, would the
> > following be more readable ?

Actually that was my original code, but I thought you would like this better :)

Thanks for the review, a v2 is on its way.

> --
> Regards,
>
> Laurent Pinchart



-- 
Ricardo Ribalda