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From: Hans Verkuil <hverkuil@xs4all.nl>
To: Sakari Ailus <sakari.ailus@iki.fi>
Cc: "Rémi Denis-Courmont" <remi@remlab.net>,
	"Laurent Pinchart" <laurent.pinchart@ideasonboard.com>,
	"Tomasz Stanislawski" <t.stanislaws@samsung.com>,
	linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
	airlied@redhat.com, m.szyprowski@samsung.com,
	kyungmin.park@samsung.com, sumit.semwal@ti.com,
	daeinki@gmail.com, daniel.vetter@ffwll.ch, robdclark@gmail.com,
	pawel@osciak.com, linaro-mm-sig@lists.linaro.org,
	subashrp@gmail.com, mchehab@redhat.com, g.liakhovetski@gmx.de
Subject: Re: [PATCHv2 3/9] v4l: add buffer exporting via dmabuf
Date: Wed, 8 Aug 2012 11:46:50 +0200	[thread overview]
Message-ID: <201208081146.50880.hverkuil@xs4all.nl> (raw)
In-Reply-To: <20120808093538.GF29636@valkosipuli.retiisi.org.uk>

On Wed 8 August 2012 11:35:38 Sakari Ailus wrote:
> Hi Hans and Rémi,
> 
> On Thu, Aug 02, 2012 at 08:35:58AM +0200, Hans Verkuil wrote:
> ...
> > Minimum or maximum? The maximum is 32, that's hardcoded in the V4L2 core.
> 
> As far as I understand, V4L1 did have that limitation, as well as videobuf1
> and 2 and a number of other drivers, but it's not found in the V4L2 core
> itself. While I'm not aware of a driver that'd allow creating more buffers
> than that the changes required to support more would be likely limited to
> videobuf2.

You are correct. It does not touch the v4l2 core, just videobuf and videobuf2.
Although the define is in videodev2.h as well, so it's something that apps
might use as well. But frankly, 32 is a very generous maximum anyway.

Only in special cases can I imagine needing more buffers (frame slicing,
high-speed capture).

Regards,

	Hans

  reply	other threads:[~2012-08-08  9:46 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-14 14:32 [PATCHv2 0/9] Support for dmabuf exporting for videobuf2 Tomasz Stanislawski
2012-06-14 14:32 ` Tomasz Stanislawski
2012-06-14 14:32 ` [PATCHv2 1/9] v4l: vb2-dma-contig: let mmap method to use dma_mmap_coherent call Tomasz Stanislawski
2012-06-14 14:32 ` [PATCHv2 2/9] Documentation: media: description of DMABUF exporting in V4L2 Tomasz Stanislawski
2012-06-14 14:32 ` [PATCHv2 3/9] v4l: add buffer exporting via dmabuf Tomasz Stanislawski
2012-07-31  6:33   ` Hans Verkuil
2012-07-31 11:56     ` Laurent Pinchart
2012-07-31 12:11       ` Hans Verkuil
2012-07-31 12:46         ` Rob Clark
2012-08-01  8:01         ` Tomasz Stanislawski
2012-08-01  8:10           ` Laurent Pinchart
2012-08-01  8:28           ` Hans Verkuil
2012-08-01  9:35             ` Tomasz Stanislawski
2012-07-31 13:39       ` Rémi Denis-Courmont
2012-07-31 14:03         ` Rob Clark
2012-07-31 14:18           ` Rémi Denis-Courmont
2012-07-31 16:28         ` Laurent Pinchart
2012-07-31 18:39           ` Rémi Denis-Courmont
2012-07-31 21:52             ` Laurent Pinchart
2012-08-01  8:37               ` Rémi Denis-Courmont
2012-08-01  8:37                 ` Rémi Denis-Courmont
2012-08-01 11:35                 ` Laurent Pinchart
2012-08-01 20:49                   ` Rémi Denis-Courmont
2012-08-02  6:35                     ` Hans Verkuil
2012-08-02  6:56                       ` Rémi Denis-Courmont
2012-08-02  7:08                         ` Hans Verkuil
2012-08-02 21:50                           ` Laurent Pinchart
2012-08-02 21:41                         ` Laurent Pinchart
2012-08-08  9:35                       ` Sakari Ailus
2012-08-08  9:46                         ` Hans Verkuil [this message]
2012-06-14 14:32 ` [PATCHv2 4/9] v4l: vb2: " Tomasz Stanislawski
2012-06-14 14:32 ` [PATCHv2 5/9] v4l: vb2-dma-contig: add support for DMABUF exporting Tomasz Stanislawski
2012-06-14 14:32 ` [PATCHv2 6/9] v4l: s5p-fimc: support for dmabuf exporting Tomasz Stanislawski
2012-06-14 14:32 ` [PATCHv2 7/9] v4l: s5p-tv: mixer: " Tomasz Stanislawski
2012-06-14 14:32 ` [PATCHv2 8/9] v4l: s5p-mfc: " Tomasz Stanislawski
2012-06-14 14:32 ` [PATCHv2 9/9] v4l: vb2-dma-contig: use dma_get_sgtable Tomasz Stanislawski

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