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From: Gerd Hoffmann <kraxel@redhat.com>
To: Dmitry Sepp <dmitry.sepp@opensynergy.com>
Cc: spice-devel@lists.freedesktop.org,
	"Keiichi Watanabe" <keiichiw@chromium.org>,
	virtio-dev@lists.oasis-open.org,
	"Tomasz Figa" <tfiga@chromium.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: Mon, 13 Jan 2020 12:05:21 +0100	[thread overview]
Message-ID: <20200113110521.5ogc3fcy4zq32yzg@sirius.home.kraxel.org> (raw)
In-Reply-To: <12433898.dW097sEU6C@os-lin-dmo>

On Mon, Jan 13, 2020 at 11:41:45AM +0100, Dmitry Sepp wrote:
> Hi Gerd,
> 
> Thanks for reviewing!
> 
> On Montag, 13. Januar 2020 10:56:36 CET Gerd Hoffmann wrote:
> >   Hi,
> > 
> > > This also means that we cannot have unspec for planes layout. Device
> > > either
> > > expects planes in separate buffers or in one buffer with some offsets,
> > > there cannot be mixed cases.
> > 
> > Hmm.  Is it useful to support both?  Or maybe support the "one buffer +
> > offsets" case only?  Splitting one buffer into multiple smaller ones
> > internally if needed shouldn't be a problem, and it would simplify the
> > interface a bit ...
> > 
> 
> Ok, let's consider the following case:
>  - the device expects planes in separate buffers.
>  - say, Android on the guest side also imports planes in separate buffers into the driver.
>  - but he driver only supports one buffer + offsets.
> 
> Do you mean the driver then can join the underlying page lists and set offsets then? Yes, 
> this would probably make sense.

Well, no.  Tomasz Figa had splitted the devices into three groups:

  (1) requires single buffer.
  (2) allows any layout (including the one (1) devices want).
  (3) requires per-plane buffers.

Category (3) devices are apparently rare and old.  Both category (1)+(2)
devices can handle single buffers just fine.  So maybe support only
that?

Hope it's more clear this time,
  Gerd


  parent reply	other threads:[~2020-01-13 11:05 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 [this message]
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

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