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Message-ID: <03187f79f37fdb45f3a774e200e21a29167776a8.camel@bootlin.com>
Subject: Re: Support for 2D engines/blitters in V4L2 and DRM
From:   Paul Kocialkowski <paul.kocialkowski@bootlin.com>
To:     Tomasz Figa <tfiga@chromium.org>
Cc:     Daniel Vetter <daniel@ffwll.ch>,
        Nicolas Dufresne <nicolas@ndufresne.ca>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Alexandre Courbot <acourbot@chromium.org>,
        Maxime Ripard <maxime.ripard@bootlin.com>,
        Hans Verkuil <hverkuil@xs4all.nl>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Linux Media Mailing List <linux-media@vger.kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
        Eric Anholt <eric@anholt.net>, Rob Clark <robdclark@gmail.com>,
        Dave Airlie <airlied@redhat.com>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Date:   Thu, 18 Apr 2019 11:13:57 +0200
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Hi,

On Thu, 2019-04-18 at 18:09 +0900, Tomasz Figa wrote:
> On Thu, Apr 18, 2019 at 5:55 PM Paul Kocialkowski
> <paul.kocialkowski@bootlin.com> wrote:
> > Hi Daniel,
> > 
> > On Thu, 2019-04-18 at 10:18 +0200, Daniel Vetter wrote:
> > > On Wed, Apr 17, 2019 at 08:10:15PM +0200, Paul Kocialkowski wrote:
> > > > Hi Nicolas,
> > > > 
> > > > I'm detaching this thread from our V4L2 stateless decoding spec since
> > > > it has drifted off and would certainly be interesting to DRM folks as
> > > > well!
> > > > 
> > > > For context: I was initially talking about writing up support for the
> > > > Allwinner 2D engine as a DRM render driver, where I'd like to be able
> > > > to batch jobs that affect the same destination buffer to only signal
> > > > the out fence once when the batch is done. We have a similar issue in
> > > > v4l2 where we'd like the destination buffer for a set of requests (each
> > > > covering one H264 slice) to be marked as done once the set was decoded.
> > > > 
> 
> Out of curiosity, what area did you find a 2D blitter useful for?

The initial motivation is to bring up a DDX with that for platforms
that have 2D engines but no free software GPU drivers yet.

I also have a personal project in the works where I'd like to implement
accelerated UI rendering in 2D. The idea is to avoid using GL entirely.

That last point is in part because I have a GPU-less device that I want
to get going with mainline: http://linux-sunxi.org/F60_Action_Camera

Cheers,

Paul

-- 
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com