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 03/15] videobuf2: add V4L2_FLAG_MEMORY_NON_CONSISTENT flag
Date: Fri, 10 Jan 2020 18:46:07 +0900 [thread overview]
Message-ID: <20200110094607.GB202391@google.com> (raw)
In-Reply-To: <750a0c62-0f0f-a5c9-1d7f-f0c5d6b620fa@xs4all.nl>
On (20/01/10 10:36), Hans Verkuil wrote:
[..]
> > diff --git a/Documentation/media/uapi/v4l/buffer.rst b/Documentation/media/uapi/v4l/buffer.rst
> > index 9149b57728e5..b08b5609f5f3 100644
> > --- a/Documentation/media/uapi/v4l/buffer.rst
> > +++ b/Documentation/media/uapi/v4l/buffer.rst
> > @@ -705,6 +705,25 @@ Buffer Flags
> >
> > .. c:type:: v4l2_memory
> >
> > +Memory Consistency Flags
> > +========================
> > +
> > +.. tabularcolumns:: |p{7.0cm}|p{2.2cm}|p{8.3cm}|
> > +
> > +.. cssclass:: longtable
> > +
> > +.. flat-table::
> > + :header-rows: 0
> > + :stub-columns: 0
> > + :widths: 3 1 4
> > +
> > + * .. _`V4L2_FLAG_MEMORY_NON_CONSISTENT`:
> > +
> > + - ``V4L2_FLAG_MEMORY_NON_CONSISTENT``
> > + - 0x00000001
> > + - Set DMA_ATTR_NON_CONSISTENT queue memory consistency bit,
> > + so all queue buffers may be allocated in non-consistent memory.
>
> This needs much more extensive documentation. This is a userspace API,
> and it shouldn't refer to a kernelspace API. Instead, explain what it
> means from a user perspective. Also, how does this relate to the cache
> buffer flags?
>
> These things are tricky, so it is worth spending some time on writing
> good documentation.
Agreed. I'll give it a shot, will try to improve it.
-ss
next prev parent reply other threads:[~2020-01-10 9:46 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 [this message]
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
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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