[Buildroot] [PATCH 1/1] package/opencv3: disable NEON and VFPv3 options

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

Hello,

On Tue, 20 Aug 2019 20:40:39 +0200
Fabrice Fontaine <fontaine.fabrice@gmail.com> wrote:

> -# * PowerPC support is turned off since its only effect is altering CFLAGS,
> -#   adding '-mcpu=G3 -mtune=G5' to them, which is already handled by Buildroot.
> +# * PowerPC, NEON and VFPv3 support are turned off since their only effects are
> +#   altering CFLAGS, adding '-mcpu=G3 -mtune=G5', '-mfpu=neon' or '-mfpu=vfpv3'
> +#   to them, which is already handled by Buildroot.
>  OPENCV3_CONF_OPTS += \
>  	-DENABLE_POWERPC=OFF \
> -	-DENABLE_NEON=$(if $(BR2_ARM_CPU_HAS_NEON),ON,OFF)
> -
> -ifeq ($(BR2_ARCH_IS_64):$(BR2_ARM_CPU_HAS_VFPV3),:y)
> -OPENCV3_CONF_OPTS += -DENABLE_VFPV3=ON
> -else
> -OPENCV3_CONF_OPTS += -DENABLE_VFPV3=OFF
> -endif
> +	-DENABLE_NEON=OFF \
> +	-DENABLE_VFPV3=OFF
>  
>  # Cuda stuff
>  OPENCV3_CONF_OPTS += \

So, we looked into it some more with Arnout, and turns out that
ENABLE_NEON=ON does more than adding options to CFLAGS, it enables some
NEON specific code in the Carotene sublibrary at least.

However, for VFPv3 indeed it is true that it was only adding CFLAGS. So
we reduced the patch to just do -DENABLE_VFPV3=OFF, and applied.

Thanks a lot!

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com