From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>,
linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
Sakari Ailus <sakari.ailus@iki.fi>,
Hans Verkuil <hans.verkuil@cisco.com>,
Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Subject: Re: [PATCH/RFC v2 4/4] v4l: vsp1: Add HGO support
Date: Fri, 24 Jun 2016 17:35:51 +0300 [thread overview]
Message-ID: <2199003.uUy7t6IokG@avalon> (raw)
In-Reply-To: <Pine.LNX.4.64.1606131726380.18676@axis700.grange>
Hi Guennadi,
On Monday 13 Jun 2016 17:33:01 Guennadi Liakhovetski wrote:
> On Thu, 12 May 2016, Laurent Pinchart wrote:
> > The HGO is a Histogram Generator One-Dimension. It computes per-channel
> > histograms over a configurable region of the image with optional
> > subsampling.
> >
> > Signed-off-by: Laurent Pinchart
> > <laurent.pinchart+renesas@ideasonboard.com>
>
> [snip]
>
> Do I understand this correctly, that with this if such a metadata device
> is opened, while no video data is streaming, all calls will succeed, but
> no buffers will be dequeued, i.e. the user-space application will hang in
> DQBUF or poll() / select() indefinitely?
That's correct. Same as with a mem-to-mem device, if you open the capture
node, queue buffers and start streaming, DQBUF will wait until you start
supplying buffers on the node at the other end of the pipeline.
--
Regards,
Laurent Pinchart
next prev parent reply other threads:[~2016-06-24 14:35 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-12 0:17 [PATCH/RFC v2 0/4] Meta-data video device type Laurent Pinchart
2016-05-12 0:18 ` [PATCH/RFC v2 1/4] v4l: Add metadata buffer type and format Laurent Pinchart
2016-05-23 10:09 ` Hans Verkuil
2016-05-24 15:28 ` Sakari Ailus
2016-05-24 15:36 ` Hans Verkuil
2016-05-24 16:26 ` Sakari Ailus
2016-06-22 16:51 ` Laurent Pinchart
2016-06-24 23:15 ` Sakari Ailus
2016-06-22 16:32 ` Laurent Pinchart
2016-05-12 0:18 ` [PATCH/RFC v2 2/4] v4l: Add metadata video device type Laurent Pinchart
2016-05-12 21:22 ` Sakari Ailus
2016-05-12 0:18 ` [PATCH/RFC v2 3/4] v4l: Define a pixel format for the R-Car VSP1 1-D histogram engine Laurent Pinchart
2016-05-12 0:18 ` [PATCH/RFC v2 4/4] v4l: vsp1: Add HGO support Laurent Pinchart
2016-06-13 15:33 ` Guennadi Liakhovetski
2016-06-24 14:35 ` Laurent Pinchart [this message]
2016-05-13 9:26 ` [PATCH/RFC v2 0/4] Meta-data video device type Hans Verkuil
2016-05-13 9:52 ` Sakari Ailus
2016-05-16 9:20 ` Laurent Pinchart
2016-05-23 13:00 ` Guennadi Liakhovetski
2016-05-16 9:21 ` Laurent Pinchart
2016-05-17 9:26 ` Sakari Ailus
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