Re: [PATCH/RFC v2 1/3] fbdev: Add FOURCC-based format configuration API

Hi Laurent,

On Mon, Aug 29, 2011 at 12:09, Laurent Pinchart
[off-list ref] wrote:

On Monday 29 August 2011 11:36:07 Geert Uytterhoeven wrote:

quoted

On Mon, Aug 29, 2011 at 10:50, Laurent Pinchart wrote:

[...]

If my understanding is now correct, a V4L2 planar YUV type where Y, U and V
components are stored in separate byte-oriented planes, with each plane
storing Y, U or V components packed (such as http://linuxtv.org/downloads/v4l-
dvb-apis/V4L2-PIX-FMT-YUV422P.html), would be of neither FB_TYPE_PLANES nor
FB_TYPE_PACKED. The same would be true for an RGB format where each component
is stored in a separate plane with each plane sotring R, G or B packed.

Indeed. Currently this cannot be represented.
For ideas from the past, see e.g.
http://comments.gmane.org/gmane.linux.fbdev.devel/10951.

If the above is correct, what FB_TYPE_* should a driver report when using
FB_VISUAL_FOURCC with V4L2_PIX_FMT_YUV422P (http://linuxtv.org/downloads/v4l-
dvb-apis/V4L2-PIX-FMT-YUV422P.html) or V4L2_PIX_FMT_NV12
(http://linuxtv.org/downloads/v4l-dvb-apis/re25.html) for instance ?

We need new types for those. Or always use FOURCC for them.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds