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

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

[Fabrice Fontaine]

Commit a17402e42d8c996af239cfdb536e74188d6c6245 has conditionally
enabled NEON and VFPv3 optimizations. However these options are passing
-mfpu=neon or -mfpu=vfpv3 to the compiler which raise issues on some
targets such as Cortex-A5 with VFPv4-D16 enabled but without NEON and
VFPv4.

So disable these options as buildroot is already passing -mfpu

Fixes:
 - https://bugs.buildroot.org/show_bug.cgi?id=11996

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
---
 package/opencv3/opencv3.mk | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/package/opencv3/opencv3.mk b/package/opencv3/opencv3.mk
index 91efa5c912..d3e795aae1 100644
--- a/package/opencv3/opencv3.mk
+++ b/package/opencv3/opencv3.mk
@@ -109,17 +109,13 @@ OPENCV3_CONF_OPTS += \
 
 # Hardware support options.
 #
-# * 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 += \
-- 
2.20.1

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

[Thomas Petazzoni]

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

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

[Peter Korsgaard]

>>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni@bootlin.com> writes:

 > 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!

Committed to 2019.02.x and 2019.11.x, thanks.

-- 
Bye, Peter Korsgaard