From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Hans Verkuil <hverkuil@xs4all.nl>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>,
Hans Verkuil <hans.verkuil@cisco.com>,
Tomasz Figa <tfiga@chromium.org>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Kyungmin Park <kyungmin.park@samsung.com>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Sakari Ailus <sakari.ailus@iki.fi>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Pawel Osciak <posciak@chromium.org>,
linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH 05/15] videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT in REQBUFS
Date: Wed, 22 Jan 2020 11:18:05 +0900 [thread overview]
Message-ID: <20200122021805.GE149602@google.com> (raw)
In-Reply-To: <8d0c95c3-64a2-ec14-0ac2-204b0430b2b4@xs4all.nl>
On (20/01/10 10:55), Hans Verkuil wrote:
> On 12/17/19 4:20 AM, Sergey Senozhatsky wrote:
> > This patch lets user-space to request a non-consistent memory
> > allocation during REQBUFS ioctl call. We use one bit of a
> > ->reserved[1] member of struct v4l2_requestbuffers, which is
> > now renamed to ->flags.
> >
> > There is just 1 four-byte reserved area in v4l2_requestbuffers
> > struct, therefore for backward compatibility ->reserved and
> > ->flags were put into anonymous union.
> >
> > Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> > ---
> > Documentation/media/uapi/v4l/vidioc-reqbufs.rst | 14 ++++++++++++--
> > drivers/media/common/videobuf2/videobuf2-v4l2.c | 14 ++++++++++++--
> > drivers/media/v4l2-core/v4l2-ioctl.c | 3 ---
> > include/uapi/linux/videodev2.h | 5 ++++-
> > 4 files changed, 28 insertions(+), 8 deletions(-)
> >
> > diff --git a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
> > index d0c643db477a..9b69a61d9fd4 100644
> > --- a/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
> > +++ b/Documentation/media/uapi/v4l/vidioc-reqbufs.rst
> > @@ -112,10 +112,20 @@ aborting or finishing any DMA in progress, an implicit
> > ``V4L2_MEMORY_MMAP`` and ``type`` set to the buffer type. This will
> > free any previously allocated buffers, so this is typically something
> > that will be done at the start of the application.
> > - * - __u32
> > + * - union
> > + - (anonymous)
> > + * -
> > + - __u32
> > + - ``flags``\ [1]
> > + - Specifies additional buffer management attributes. E.g. when
> > + ``V4L2_FLAG_MEMORY_NON_CONSISTENT`` set vb2 backends may be allocated
> > + in non-consistent memory.
>
> This should link to the table with these memory flags, rather than
> effectively documenting V4L2_FLAG_MEMORY_NON_CONSISTENT again.
OK.
> You also probably meant "vb2 buffers" rather than "vb2 backends".
Thanks.
>
> > + * -
> > + - __u32
> > - ``reserved``\ [1]
> > - A place holder for future extensions. Drivers and applications
> > - must set the array to zero.
> > + must set the array to zero, unless application wants to specify
> > + buffer management ``flags``.
>
> I think support for this flag should be signaled as a V4L2_BUF_CAP capability.
> If the capability is not set, then vb2 should set 'flags' to 0 to preserve the
> old 'Drivers and applications must set the array to zero' behavior.
The patch set adds V4L2_BUF_CAP_SUPPORTS_CACHE_HINTS towards the end of the
series, I guess I can shuffle the patches and change the wording here.
> The documentation for 'reserved[1]' should be changed to something like:
>
> Kept for backwards compatibility. Use ``flags`` instead.
OK.
-ss
next prev parent reply other threads:[~2020-01-22 2:18 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-17 3:20 [RFC][PATCH 00/15] Implement V4L2_BUF_FLAG_NO_CACHE_* flags Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 01/15] videobuf2: add cache management members Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 02/15] videobuf2: handle V4L2 buffer cache flags Sergey Senozhatsky
2020-01-10 10:24 ` Hans Verkuil
2020-01-22 1:39 ` Sergey Senozhatsky
2020-01-22 2:53 ` Sergey Senozhatsky
2020-01-28 4:35 ` Tomasz Figa
2019-12-17 3:20 ` [RFC][PATCH 03/15] videobuf2: add V4L2_FLAG_MEMORY_NON_CONSISTENT flag Sergey Senozhatsky
2020-01-10 9:36 ` Hans Verkuil
2020-01-10 9:46 ` Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 04/15] videobuf2: add queue memory consistency parameter Sergey Senozhatsky
2020-01-10 9:47 ` Hans Verkuil
2020-01-22 2:05 ` Sergey Senozhatsky
2020-01-23 11:02 ` Hans Verkuil
2020-01-24 2:04 ` Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 05/15] videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT in REQBUFS Sergey Senozhatsky
2020-01-10 9:55 ` Hans Verkuil
2020-01-22 2:18 ` Sergey Senozhatsky [this message]
2020-01-22 3:48 ` Sergey Senozhatsky
2020-01-23 11:08 ` Hans Verkuil
2020-01-28 4:45 ` Tomasz Figa
2020-01-28 8:38 ` Hans Verkuil
2019-12-17 3:20 ` [RFC][PATCH 06/15] videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT in CREATE_BUFS Sergey Senozhatsky
2020-01-10 9:59 ` Hans Verkuil
2020-01-23 3:41 ` Sergey Senozhatsky
2020-01-23 11:41 ` Hans Verkuil
2020-01-24 1:28 ` Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 07/15] videobuf2: factor out planes prepare/finish functions Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 08/15] videobuf2: do not sync caches when we are allowed not to Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 09/15] videobuf2: check ->synced flag in prepare() and finish() Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 10/15] videobuf2: let user-space know when driver supports cache hints Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 11/15] videobuf2: add begin/end cpu_access callbacks to dma-contig Sergey Senozhatsky
2019-12-17 3:20 ` [RFC][PATCH 12/15] videobuf2: add begin/end cpu_access callbacks to dma-sg Sergey Senozhatsky
2020-01-10 10:13 ` Hans Verkuil
2020-01-22 6:37 ` Sergey Senozhatsky
2020-01-28 4:38 ` Tomasz Figa
2020-01-28 8:36 ` Hans Verkuil
2020-01-30 11:02 ` Tomasz Figa
2020-01-30 12:18 ` Hans Verkuil
2020-02-03 10:04 ` Tomasz Figa
2020-02-04 2:50 ` Sergey Senozhatsky
2020-02-06 8:51 ` Tomasz Figa
2019-12-17 3:20 ` [RFC][PATCH 13/15] videobuf2: do not sync buffers for DMABUF queues Sergey Senozhatsky
2020-01-10 10:30 ` Hans Verkuil
2020-01-22 5:05 ` Sergey Senozhatsky
2020-01-23 11:35 ` Hans Verkuil
2020-01-24 2:25 ` Sergey Senozhatsky
2020-01-24 7:32 ` Sergey Senozhatsky
2020-01-28 7:22 ` Tomasz Figa
2020-01-28 7:34 ` Sergey Senozhatsky
2020-01-28 7:19 ` Tomasz Figa
2020-01-28 8:47 ` Hans Verkuil
2019-12-17 3:20 ` [RFC][PATCH 14/15] videobuf2: don't test db_attach in dma-contig prepare and finish Sergey Senozhatsky
2020-01-10 10:32 ` Hans Verkuil
2019-12-17 3:20 ` [RFC][PATCH 15/15] videobuf2: don't test db_attach in dma-sg " Sergey Senozhatsky
2020-01-08 2:27 ` [RFC][PATCH 00/15] Implement V4L2_BUF_FLAG_NO_CACHE_* flags Sergey Senozhatsky
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