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[media] v4l: Support extending the v4l2_pix_format structure

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The v4l2_pix_format structure has no reserved field. It is embedded in
the v4l2_framebuffer structure which has no reserved fields either, and
in the v4l2_format structure which has reserved fields that were not
previously required to be zeroed out by applications.

To allow extending v4l2_pix_format, inline it in the v4l2_framebuffer
structure, and use the priv field as a magic value to indicate that the
application has set all v4l2_pix_format extended fields and zeroed all
reserved fields following the v4l2_pix_format field in the v4l2_format
structure.

The availability of this API extension is reported to userspace through
the new V4L2_CAP_EXT_PIX_FORMAT capability flag. Just checking that the
priv field is still set to the magic value at [GS]_FMT return wouldn't
be enough, as older kernels don't zero the priv field on return.

To simplify the internal API towards drivers zero the extended fields
and set the priv field to the magic value for applications not aware of
the extensions.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
This commit is contained in:
Laurent Pinchart 2014-05-27 09:41:05 -03:00 • committed by Mauro Carvalho Chehab
commit d52e238136
31 changed files with 134 additions and 70 deletions
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15
include/uapi/linux/videodev2.h
View file

@ -268,6 +268,7 @@ struct v4l2_capability {
#define V4L2_CAP_MODULATOR 0x00080000 /* has a modulator */
#define V4L2_CAP_SDR_CAPTURE 0x00100000 /* Is a SDR capture device */
#define V4L2_CAP_EXT_PIX_FORMAT 0x00200000 /* Supports the extended pixel format */
#define V4L2_CAP_READWRITE 0x01000000 /* read/write systemcalls */
#define V4L2_CAP_ASYNCIO 0x02000000 /* async I/O */
@ -448,6 +449,9 @@ struct v4l2_pix_format {
#define V4L2_SDR_FMT_CU8 v4l2_fourcc('C', 'U', '0', '8') /* IQ u8 */
#define V4L2_SDR_FMT_CU16LE v4l2_fourcc('C', 'U', '1', '6') /* IQ u16le */
/* priv field value to indicates that subsequent fields are valid. */
#define V4L2_PIX_FMT_PRIV_MAGIC 0xfeedcafe
/*
* F O R M A T E N U M E R A T I O N
*/
@ -752,7 +756,16 @@ struct v4l2_framebuffer {
/* FIXME: in theory we should pass something like PCI device + memory
* region + offset instead of some physical address */
void *base;
struct v4l2_pix_format fmt;
struct {
__u32 width;
__u32 height;
__u32 pixelformat;
__u32 field; /* enum v4l2_field */
__u32 bytesperline; /* for padding, zero if unused */
__u32 sizeimage;
__u32 colorspace; /* enum v4l2_colorspace */
__u32 priv; /* reserved field, set to 0 */
} fmt;
};
/* Flags for the 'capability' field. Read only */
#define V4L2_FBUF_CAP_EXTERNOVERLAY 0x0001