On Thu, Sep 01, 2011 at 09:03:52AM +0200, Guennadi Liakhovetski wrote:
> Hi Sakari
Hi Guennadi,
> On Thu, 1 Sep 2011, Sakari Ailus wrote:
[clip]
> > > diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
> > > index fca24cc..988e1be 100644
> > > --- a/include/linux/videodev2.h
> > > +++ b/include/linux/videodev2.h
> > > @@ -653,6 +653,9 @@ struct v4l2_buffer {
> > > #define V4L2_BUF_FLAG_ERROR 0x0040
> > > #define V4L2_BUF_FLAG_TIMECODE 0x0100 /* timecode field is valid */
> > > #define V4L2_BUF_FLAG_INPUT 0x0200 /* input field is valid */
> > > +/* Cache handling flags */
> > > +#define V4L2_BUF_FLAG_NO_CACHE_INVALIDATE 0x0400
> > > +#define V4L2_BUF_FLAG_NO_CACHE_CLEAN 0x0800
> > >
> > > /*
> > > * O V E R L A Y P R E V I E W
> > > @@ -2092,6 +2095,15 @@ struct v4l2_dbg_chip_ident {
> > > __u32 revision; /* chip revision, chip specific */
> > > } __attribute__ ((packed));
> > >
> > > +/* VIDIOC_CREATE_BUFS */
> > > +struct v4l2_create_buffers {
> > > + __u32 index; /* output: buffers
> > > index...index + count - 1 have been created */
> > > + __u32 count;
> > > + enum v4l2_memory memory;
> > > + struct v4l2_format format; /* "type" is used always, the
> > > rest if sizeimage == 0 */
> > > + __u32 reserved[8];
> > > +};
> >
> > How about splitting the above comments? These lines are really long.
> > Kerneldoc could also be used, I think.
>
> Sure, how about this incremental patch:
>
> From: Guennadi Liakhovetski <[email protected]>
> Subject: V4L: improve struct v4l2_create_buffers documentation
>
> Signed-off-by: Guennadi Liakhovetski <[email protected]>
> ---
> diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
> index 988e1be..64e0bf2 100644
> --- a/include/linux/videodev2.h
> +++ b/include/linux/videodev2.h
> @@ -2095,12 +2095,20 @@ struct v4l2_dbg_chip_ident {
> __u32 revision; /* chip revision, chip specific */
> } __attribute__ ((packed));
>
> -/* VIDIOC_CREATE_BUFS */
> +/**
> + * struct v4l2_create_buffers - VIDIOC_CREATE_BUFS argument
> + * @index: on return, index of the first created buffer
> + * @count: entry: number of requested buffers,
> + * return: number of created buffers
> + * @memory: buffer memory type
> + * @format: frame format, for which buffers are requested
> + * @reserved: future extensions
> + */
> struct v4l2_create_buffers {
> - __u32 index; /* output: buffers
> index...index + count - 1 have been created */
> + __u32 index;
> __u32 count;
> enum v4l2_memory memory;
> - struct v4l2_format format; /* "type" is used always, the
> rest if sizeimage == 0 */
> + struct v4l2_format format;
> __u32 reserved[8];
> };
Thanks! This looks good to me. Could you do a similar change to the
compat-IOCTL version of this struct (v4l2_create_buffers32)?
> > > +
> > > /*
> > > * I O C T L C O D E S F O R V I D E O D E V I C E S
> > > *
> > > @@ -2182,6 +2194,9 @@ struct v4l2_dbg_chip_ident {
> > > #define VIDIOC_SUBSCRIBE_EVENT _IOW('V', 90, struct
> > > v4l2_event_subscription)
> > > #define VIDIOC_UNSUBSCRIBE_EVENT _IOW('V', 91, struct
> > > v4l2_event_subscription)
> > >
> > > +#define VIDIOC_CREATE_BUFS _IOWR('V', 92, struct
> > > v4l2_create_buffers)
> > > +#define VIDIOC_PREPARE_BUF _IOW('V', 93, struct v4l2_buffer)
> >
> > Does prepare_buf ever do anything that would need to return anything to the
> > user? I guess the answer is "no"?
>
> Exactly, that's why it's an "_IOW" ioctl(), not an "_IOWR", or have I
> misunderstood you?
I was thinking if this will be the case now and in the foreseeable future as
this can't be changed after once defined. I just wanted to bring this up
even though I don't see myself that any of the fields would need to be
returned to the user. But there are reserved fields...
So unless someone comes up with something quick, I think this should stay
as-is.
--
Sakari Ailus
[email protected]
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