From: Keiichi Watanabe <keiichiw@chromium.org>
To: Gerd Hoffmann <kraxel@redhat.com>
Cc: "Tomasz Figa" <tfiga@chromium.org>,
"Dmitry Sepp" <dmitry.sepp@opensynergy.com>,
spice-devel@lists.freedesktop.org,
virtio-dev@lists.oasis-open.org,
"Linux Media Mailing List" <linux-media@vger.kernel.org>,
"Alexandre Courbot" <acourbot@chromium.org>,
"Alex Lau" <alexlau@chromium.org>,
"Daniel Vetter" <daniel@ffwll.ch>,
"Dylan Reid" <dgreid@chromium.org>,
"Enrico Granata" <egranata@google.com>,
"Frediano Ziglio" <fziglio@redhat.com>,
"Hans Verkuil" <hverkuil@xs4all.nl>,
"Stéphane Marchesin" <marcheu@chromium.org>,
"Pawel Osciak" <posciak@chromium.org>,
"David Stevens" <stevensd@chromium.org>,
uril@redhat.com
Subject: Re: [virtio-dev] Re: [PATCH v2 0/1] VirtIO video device specification
Date: Tue, 21 Jan 2020 17:56:05 +0900 [thread overview]
Message-ID: <CAD90VcaTtCdrhnPhhDWrheF2xrgF-LXL94MPZy9BfHB-Wh9FwQ@mail.gmail.com> (raw)
In-Reply-To: <20200121064437.jryf3lq72bucs6rr@sirius.home.kraxel.org>
Hi,
On Tue, Jan 21, 2020 at 3:44 PM Gerd Hoffmann <kraxel@redhat.com> wrote:
>
> > > > Can't this problem be solved by adding "offset" field in virtio_video_mem_entry?
> > > >
> > > > struct virtio_video_mem_entry {
> > > > le64 addr;
> > > > le32 length;
> > > > le32 offset;
> > > > u8 padding[4];
> > > > };
> > > >
> > > > Here, "addr" must be the same in every mem_entry for (1) hardware.
> > >
> > > No. virtio_video_mem_entry is basically a scatter list entry, you use
> > > an *array* of these entries to describe your buffer (unless you are
> > > using CMA due to hardware requirements, in this special case you have
> > > only one entry in your array).
> >
> > I see. I forgot about scatter list.
> > However, I'm still not sure about the usage for CMA.
> > if we're using CMA for a multiplanar format, how can the device know
> > where the second plane start from?
> > In my understanding, the number of entries in this case should be the
> > same with the number of planes and
> > "entries[0].addr + entries[0].length == entries[1].addr" should hold.
>
> With the one-buffer-per-frame model you could add a plane_offsets[4]
> field to virtio_video_resource_create.
>
> The virtio_video_mem_entry array describes the whole buffer for all
> planes, the plane_offsets array says where the individual planes start
> inside the buffer.
Got it. It makes sense to have plane_offsets[] separately.
Thanks!
Best regards,
Keiichi
>
> cheers,
> Gerd
>
>
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>
prev parent reply other threads:[~2020-01-21 8:56 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-18 13:02 [PATCH v2 0/1] VirtIO video device specification Keiichi Watanabe
2019-12-18 13:02 ` [PATCH v2 1/1] virtio-video: Add virtio " Keiichi Watanabe
2019-12-18 13:40 ` Gerd Hoffmann
2019-12-18 14:08 ` [virtio-dev] " Tomasz Figa
2019-12-19 7:46 ` Gerd Hoffmann
2019-12-19 9:48 ` Dmitry Sepp
2019-12-19 9:59 ` Tomasz Figa
2019-12-19 10:54 ` Dmitry Sepp
2019-12-19 12:05 ` Tomasz Figa
2019-12-19 13:12 ` Gerd Hoffmann
2020-01-08 13:52 ` Keiichi Watanabe
2020-01-09 13:40 ` Gerd Hoffmann
2020-01-09 14:20 ` Tomasz Figa
2020-01-14 7:18 ` Keiichi Watanabe
2020-01-14 10:35 ` Dmitry Sepp
2020-01-15 7:49 ` Keiichi Watanabe
2020-01-15 11:12 ` Tomasz Figa
2019-12-19 13:01 ` Gerd Hoffmann
2020-01-08 13:50 ` Keiichi Watanabe
2019-12-19 9:26 ` Dmitry Sepp
2019-12-19 9:59 ` Tomasz Figa
2019-12-19 12:54 ` Gerd Hoffmann
2019-12-18 17:29 ` Frediano Ziglio
2019-12-20 14:05 ` Keiichi Watanabe
2019-12-20 15:33 ` Dmitry Sepp
2019-12-19 13:28 ` Dmitry Sepp
2019-12-20 15:26 ` Keiichi Watanabe
[not found] ` <2584386.DF4NACHtsB@os-lin-dmo>
2019-12-21 6:46 ` Tomasz Figa
2019-12-30 12:16 ` [virtio-dev] " Dmitry Sepp
2020-01-06 6:31 ` Tomasz Figa
2020-01-06 8:33 ` Gerd Hoffmann
2020-01-06 9:29 ` Dmitry Sepp
2020-01-03 15:47 ` Dmitry Sepp
2020-01-06 8:47 ` Gerd Hoffmann
2020-01-06 10:21 ` Keiichi Watanabe
2020-01-06 14:59 ` Dmitry Sepp
2020-01-07 13:24 ` Keiichi Watanabe
2020-01-07 16:50 ` Dmitry Sepp
2020-01-08 6:59 ` Keiichi Watanabe
2020-01-08 10:00 ` Dmitry Sepp
2020-01-08 12:14 ` Keiichi Watanabe
2020-01-08 12:46 ` Tomasz Figa
2020-01-08 13:05 ` Keiichi Watanabe
2020-01-08 13:11 ` Dmitry Sepp
2020-01-08 13:23 ` [virtio-dev] " Keiichi Watanabe
2020-01-08 12:23 ` Keiichi Watanabe
2019-12-20 15:58 ` [PATCH v2 0/1] VirtIO " Dmitry Sepp
2019-12-21 4:36 ` Keiichi Watanabe
2019-12-21 6:18 ` Tomasz Figa
2019-12-21 6:19 ` Tomasz Figa
2020-01-03 13:05 ` Dmitry Sepp
2020-01-06 10:30 ` Keiichi Watanabe
2020-01-06 11:28 ` Dmitry Sepp
2020-01-07 10:25 ` Keiichi Watanabe
2020-01-09 14:56 ` Dmitry Sepp
2020-01-10 10:16 ` [virtio-dev] " Dmitry Sepp
2020-01-10 13:53 ` Keiichi Watanabe
2020-01-10 15:11 ` Dmitry Sepp
2020-01-11 16:06 ` Tomasz Figa
2020-01-13 9:50 ` Dmitry Sepp
2020-01-15 11:23 ` Keiichi Watanabe
2020-01-13 9:56 ` Gerd Hoffmann
[not found] ` <12433898.dW097sEU6C@os-lin-dmo>
2020-01-13 11:05 ` Gerd Hoffmann
2020-01-13 11:59 ` Tomasz Figa
2020-01-13 13:26 ` Gerd Hoffmann
2020-01-15 11:00 ` Tomasz Figa
2020-01-15 11:23 ` Keiichi Watanabe
2020-01-15 11:26 ` Gerd Hoffmann
2020-01-20 7:20 ` Keiichi Watanabe
2020-01-20 10:47 ` Gerd Hoffmann
2020-01-21 2:47 ` Keiichi Watanabe
2020-01-21 6:44 ` Gerd Hoffmann
2020-01-21 8:56 ` Keiichi Watanabe [this message]
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