Emulation of Linux V4L ioctls

[J.R. Oldroyd]

On Fri, 20 Nov 2009 10:35:35 +0100, Alexander Leidinger <Alexander at leidinger.net> wrote:
>
> Some things I noticed and worry about:
>   - videodev.h does not have a license, did you generate it
>     yourself or did you take it from somewhere?
>   - Does it needs to be named videodev.h, or can it also be
>     linux_videodev.h?
>     (if we may want to install this header at some point in time,
>     it should have a name compatible with linux, else we should
>     maybe add a linux_ prefix for consistence and for making it
>     very obvious what we are talking about)
>   - Why are you using __s32 and so on instead of the normal
>     fixed size int types? We also have lint for "linux int"
>     and so on in other files.

This header is the same as the one used on Linux.  In fact, I
took this file from our pwcbsd driver, but it can also be found
by googling for videodev.h which reveals it is
    /usr/include/linux/videodev.h
on Linux 2.6 systems.

I think it really wants to be installed in /usr/include/linux
here too, since it is also useful for user apps that need
these structures and definitions.  But I am not sure what our
policy would be for creating a /usr/include/linux dir for it.

If you prefer to keep it in this dir, yes it could be renamed
to linux_videodev.h.

There is indeed no license in this file.

The use of __s32 etc is because I used this file unchanged.

>   - On which architecture has this been tested?
>   - Will it run in linux32 emulation on amd64?

Yes.  I did this work on an amd64, in fact.

>   - Are those structures known in userland (and as such need to
>     have a specific size)? If yes, do they have different sizes
>     in linux depending if the kernel is a 64bit kernel (amd64)
>     or 32bit kernel (x86)?

They are used in userland.  Given the header's use of __s32
etc, it looks to me like the structures have the same size
on both x86 and amd64.

>   - Has this been run through a "make universe"?
> 
I built by compiling in sys/amd64/compile/XXX.

	-jr