From: Mauro Carvalho Chehab <mchehab@redhat.com>
To: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Pawel Osciak <p.osciak@samsung.com>,
linux-media@vger.kernel.org, kyungmin.park@samsung.com,
t.fujak@samsung.com
Subject: Re: [PATCH/RFC v1 0/7] Videobuf2 framework
Date: Fri, 10 Sep 2010 09:15:16 -0300 [thread overview]
Message-ID: <4C8A2154.8090401@redhat.com> (raw)
In-Reply-To: <4C89E084.6090203@samsung.com>
Em 10-09-2010 04:38, Marek Szyprowski escreveu:
> Hello,
>
> On 2010-09-10 13:27, Mauro Carvalho Chehab wrote:
>
>>>> 1) it lacks implementation of read() method. This means that vivi driver
>>>> has a regression, as it currently supports it.
>>>
>>> Yes, read() is not yet implemented. I guess it is not a feature that would
>>> be deprecated, right?
>>
>> Yes, there are no plans to deprecate it. Also, some devices like cx88 and bttv
>> allows receiving simultaneous streams, one via mmap, and another via read().
>> This is used by some applications to allow recording video via ffmpeg/mencoder
>> using read(), while the main application is displaying video using mmap.
>
> Well, in my opinion such devices should provide two separate /dev/videoX nodes rather than hacking with mmap and read access types.
Why? V4L2 API allows to have multiple applications opening and streaming. There's nothing
wrong with that, since it is a common practice in Unix to allow multiple opens for the same
device.
Cheers,
Mauro
prev parent reply other threads:[~2010-09-10 12:15 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-09 9:19 [PATCH/RFC v1 0/7] Videobuf2 framework Pawel Osciak
2010-09-09 9:19 ` [PATCH v1 1/7] v4l: add videobuf2 Video for Linux 2 driver framework Pawel Osciak
2010-09-09 17:29 ` Mauro Carvalho Chehab
2010-09-15 20:16 ` Pawel Osciak
2010-09-25 14:27 ` Hans Verkuil
2010-09-29 23:40 ` Pawel Osciak
2010-09-09 9:19 ` [PATCH v1 2/7] v4l: videobuf2: add generic memory handling routines Pawel Osciak
2010-09-09 17:34 ` Mauro Carvalho Chehab
2010-09-09 9:19 ` [PATCH v1 3/7] v4l: mem2mem: port to videobuf2 Pawel Osciak
2010-09-09 9:19 ` [PATCH v1 4/7] v4l: videobuf2: add vmalloc allocator Pawel Osciak
2010-09-09 9:19 ` [PATCH v1 5/7] v4l: videobuf2: add DMA coherent allocator Pawel Osciak
2010-09-09 9:19 ` [PATCH v1 6/7] v4l: vivi: port to videobuf2 Pawel Osciak
2010-09-09 9:19 ` [PATCH v1 7/7] v4l: videobuf2: add CMA allocator Pawel Osciak
2010-09-15 8:55 ` han jonghun
2010-09-15 20:25 ` Pawel Osciak
2010-09-09 9:26 ` [PATCH/RFC v1 0/7] Videobuf2 framework Pawel Osciak
2010-09-09 17:53 ` Mauro Carvalho Chehab
2010-09-10 3:20 ` Pawel Osciak
2010-09-10 4:27 ` Mauro Carvalho Chehab
2010-09-10 7:38 ` Marek Szyprowski
2010-09-10 8:22 ` Hans Verkuil
2010-09-10 8:26 ` Devin Heitmueller
2010-09-10 13:50 ` Andy Walls
2010-09-10 12:15 ` Mauro Carvalho Chehab [this message]
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