What to do with videodev.h

What to do with videodev.h

[Hans de Goede]

Hi All,

With v4l1 support going completely away, the question is
raised what to do with linux/videodev.h .

Since v4l1 apps can still use the old API through libv4l1,
these apps will still need linux/videodev.h to compile.

So I see 3 options:
1) Keep videodev.h in the kernel tree even after we've dropped
the API support at the kernel level (seems like a bad idea to me)
2) Copy videodev.h over to v4l-utils as is (under a different name)
and modify the #include in libv4l1.h to include it under the
new name
3) Copy the (needed) contents of videodev.h over to libv4l1.h

I'm not sure where I stand wrt 2 versus 3. Comments anyone?

Regards,

Hans

Re: What to do with videodev.h

[Mauro Carvalho Chehab]

Hi Hans,

Em 26-01-2011 06:26, Hans de Goede escreveu:
> Hi All,
> 
> With v4l1 support going completely away, the question is
> raised what to do with linux/videodev.h .
> 
> Since v4l1 apps can still use the old API through libv4l1,
> these apps will still need linux/videodev.h to compile.
> 
> So I see 3 options:
> 1) Keep videodev.h in the kernel tree even after we've dropped
> the API support at the kernel level (seems like a bad idea to me)

That's a bad idea.

> 2) Copy videodev.h over to v4l-utils as is (under a different name)
> and modify the #include in libv4l1.h to include it under the
> new name
> 3) Copy the (needed) contents of videodev.h over to libv4l1.h

I would do (3). This provides a clearer signal that V4L1-only apps need
to use libv4l1, or otherwise will stop working.

Of course, the better is to remove V4L1 support from those old apps.
There are a number of applications that support both API's. So, it
is time to remove V4L1 support from them.

> I'm not sure where I stand wrt 2 versus 3. Comments anyone?

Cheers,
Mauro

Re: What to do with videodev.h

[Hans Verkuil]

> Hi Hans,
>
> Em 26-01-2011 06:26, Hans de Goede escreveu:
>> Hi All,
>>
>> With v4l1 support going completely away, the question is
>> raised what to do with linux/videodev.h .
>>
>> Since v4l1 apps can still use the old API through libv4l1,
>> these apps will still need linux/videodev.h to compile.
>>
>> So I see 3 options:
>> 1) Keep videodev.h in the kernel tree even after we've dropped
>> the API support at the kernel level (seems like a bad idea to me)
>
> That's a bad idea.
>
>> 2) Copy videodev.h over to v4l-utils as is (under a different name)
>> and modify the #include in libv4l1.h to include it under the
>> new name
>> 3) Copy the (needed) contents of videodev.h over to libv4l1.h
>
> I would do (3). This provides a clearer signal that V4L1-only apps need
> to use libv4l1, or otherwise will stop working.

I agree with this.

> Of course, the better is to remove V4L1 support from those old apps.
> There are a number of applications that support both API's. So, it
> is time to remove V4L1 support from them.

So who is going to do that work? That's the problem...

But ensuring that they no longer compile is a good start :-)

Although most have a private copy of videodev.h as part of their sources.

Regards,

     Hans

>> I'm not sure where I stand wrt 2 versus 3. Comments anyone?
>
> Cheers,
> Mauro
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-- 
Hans Verkuil - video4linux developer - sponsored by Cisco

Re: What to do with videodev.h

[Mauro Carvalho Chehab]

Em 26-01-2011 07:47, Hans Verkuil escreveu:
>> Hi Hans,
>>
>> Em 26-01-2011 06:26, Hans de Goede escreveu:
>>> Hi All,
>>>
>>> With v4l1 support going completely away, the question is
>>> raised what to do with linux/videodev.h .
>>>
>>> Since v4l1 apps can still use the old API through libv4l1,
>>> these apps will still need linux/videodev.h to compile.
>>>
>>> So I see 3 options:
>>> 1) Keep videodev.h in the kernel tree even after we've dropped
>>> the API support at the kernel level (seems like a bad idea to me)
>>
>> That's a bad idea.
>>
>>> 2) Copy videodev.h over to v4l-utils as is (under a different name)
>>> and modify the #include in libv4l1.h to include it under the
>>> new name
>>> 3) Copy the (needed) contents of videodev.h over to libv4l1.h
>>
>> I would do (3). This provides a clearer signal that V4L1-only apps need
>> to use libv4l1, or otherwise will stop working.
> 
> I agree with this.
> 
>> Of course, the better is to remove V4L1 support from those old apps.
>> There are a number of applications that support both API's. So, it
>> is time to remove V4L1 support from them.
> 
> So who is going to do that work? That's the problem...
> 
> But ensuring that they no longer compile is a good start :-)
> 
> Although most have a private copy of videodev.h as part of their sources.

The ones that don't have videodev.h will compile-break on distros. So distros
will need to do something to keep it working, or they'll just drop those
pre-historic beasts. It is the Evolution Theory working for software:
to adapt or to be extinguished ;)

The ones that are shipped with videodev.h and weren't converted to libv4l
might eventually stay there for a longer time, as people will only notice
when a bug will be reported. If we know what are those apps, then we can
add a blacklist at linuxtv and/or contact interested parties on fixing/removing
them.

We should touch the tools that we care of. Maybe Devin could change tvtime,
we should remove V4L1 driver from xawtv3/xawtv4.

Regards,
Mauro

Re: What to do with videodev.h

[Devin Heitmueller]

On Wed, Jan 26, 2011 at 6:36 AM, Mauro Carvalho Chehab
<mchehab@redhat.com> wrote:
> We should touch the tools that we care of. Maybe Devin could change tvtime,
> we should remove V4L1 driver from xawtv3/xawtv4.

Yeah, I have some tvtime work planned, and dropping v4l1 was
definitely on the list.  I actually dropped the private versions of
videodev.h/videodev2.h from my repo, so I won't have much choice.

Devin

-- 
Devin J. Heitmueller - Kernel Labs
http://www.kernellabs.com