[Buildroot] [PATCH v1] package/libv4l: disable libraries build if no fork() support

Hugues FRUCHET hugues.fruchet at st.com
Wed Jul 26 09:46:58 UTC 2017


Hi Thomas,

Your patch is definitely better for sure ;)

Tested OK on my side, I will push it on media list.
Peter, could you test on your side to be sure that build issue is fixed 
on your side ?

Best regards,
Hugues.

On 07/25/2017 09:34 PM, Thomas Petazzoni wrote:
> Hello,
> 
> On Tue, 25 Jul 2017 15:29:30 +0200, Hugues Fruchet wrote:
>> Some no-MMU platforms have shared libraries support
>> but no fork() support, which is required by libv4lconvert.
>> Fix this by disabling libv4l libraries build in case of
>> no fork() support.
>> This fix the build issue reported here:
>> http://lists.buildroot.org/pipermail/buildroot/2017-July/197571.html
>>
>> Signed-off-by: Hugues Fruchet <hugues.fruchet at st.com>
> 
> I'm sorry, but I'm not sure this is the right solution. Indeed, this
> entirely disables the build of all libv4l libraries.
> 
> Therefore, if you for example re-enable the v4l2grab package by
> dropping its BR2_USE_MMU dependency, it fails to build with:
> 
> v4l2grab.c:59:21: fatal error: libv4l2.h: No such file or directory
>   #include <libv4l2.h>
> 
> So things work today because the libv4l package used to have a
> BR2_USE_MMU dependency, which was propagated to its reverse
> dependencies. But as you can see, it doesn't really work properly.
> 
> I believe the attached patch for libv4l is better. It keeps building
> all libraries, and only disables the one specific libv4lconvert feature
> that needs fork(): using external helpers for decompressing frames.
> This is only needed for the OV511 and OV518 formats, so only for very
> specific webcams if I understood correctly.
> 
> If you're happy with this patch, could you submit it upstream, and
> submit it to Buildroot as well ?
> 
> Thanks!
> 
> Thomas
> 


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