* [Buildroot] [PATCH 1/3] ffmpeg: disable for ARMv7-M
@ 2016-08-10 21:29 Thomas Petazzoni
2016-08-10 21:29 ` [Buildroot] [PATCH 2/3] ffmpeg: explicitly disable NEON support Thomas Petazzoni
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Thomas Petazzoni @ 2016-08-10 21:29 UTC (permalink / raw)
To: buildroot
In the ffmpeg code, libavutil/arm/asm.S makes some assumption about the
ARM architecture for which the code is built. Only ARMv4, ARMv5, ARMv6
and ARMv7-A is supported. Due to this, object files built out of
ARM-optimized assembly code have the wrong architecture information,
causing a failure at link time.
Adding ARMv7-M support would be possible, but it doesn't exist yet in
ffmpeg, and it's pretty unlikely that ffmpeg will ever be needed on an
ARMv7-M platform, so this commit takes the simple approach of disabling
ffmpeg for ARMv7-M.
Fixes:
http://autobuild.buildroot.net/results/ca4c67b093afd6f14349fcdc87b02e0480172e8c/
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
package/ffmpeg/Config.in | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/package/ffmpeg/Config.in b/package/ffmpeg/Config.in
index 096ff95..3a7bfd3 100644
--- a/package/ffmpeg/Config.in
+++ b/package/ffmpeg/Config.in
@@ -2,7 +2,9 @@ config BR2_PACKAGE_FFMPEG_ARCH_SUPPORTS
bool
# fenv.h lacks FE_INVALID, FE_OVERFLOW & FE_UNDERFLOW on nios2
# ffmpeg's configure script only supports mips64 (r1) variant
- default y if !BR2_nios2 && !BR2_mips_64r2 && !BR2_mips_64r6
+ # No support for ARMv7-M in the ARM assembly logic
+ default y if !BR2_nios2 && !BR2_mips_64r2 && !BR2_mips_64r6 && \
+ !BR2_ARM_CPU_ARMV7M
menuconfig BR2_PACKAGE_FFMPEG
bool "ffmpeg"
--
2.7.4
^ permalink raw reply related [flat|nested] 7+ messages in thread* [Buildroot] [PATCH 2/3] ffmpeg: explicitly disable NEON support
2016-08-10 21:29 [Buildroot] [PATCH 1/3] ffmpeg: disable for ARMv7-M Thomas Petazzoni
@ 2016-08-10 21:29 ` Thomas Petazzoni
2016-08-12 5:30 ` Khem Raj
2016-08-16 22:01 ` Peter Korsgaard
2016-08-10 21:29 ` [Buildroot] [PATCH 3/3] ffmpeg: don't pass --enable-mipsfpu on non-MIPS platform Thomas Petazzoni
2016-08-11 13:03 ` [Buildroot] [PATCH 1/3] ffmpeg: disable for ARMv7-M Thomas Petazzoni
2 siblings, 2 replies; 7+ messages in thread
From: Thomas Petazzoni @ 2016-08-10 21:29 UTC (permalink / raw)
To: buildroot
When BR2_ARM_CPU_HAS_NEON=y, we pass --enable-neon. However, when
BR2_ARM_CPU_HAS_NEON is disabled, we don't pass anything. This generally
works fine, but turned out to integrate NEON code in ARMv7-M
builds (since it's ARMv7, ffmpeg assumed it should enable NEON code).
Even though ffmpeg is now disabled for ARMv7-M, it still makes sense to
be explicit, and disable NEON support when the CPU doesn't have it.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
package/ffmpeg/ffmpeg.mk | 2 ++
1 file changed, 2 insertions(+)
diff --git a/package/ffmpeg/ffmpeg.mk b/package/ffmpeg/ffmpeg.mk
index c42336f..2b4219a 100644
--- a/package/ffmpeg/ffmpeg.mk
+++ b/package/ffmpeg/ffmpeg.mk
@@ -437,6 +437,8 @@ FFMPEG_CONF_OPTS += --disable-vfp
endif
ifeq ($(BR2_ARM_CPU_HAS_NEON),y)
FFMPEG_CONF_OPTS += --enable-neon
+else
+FFMPEG_CONF_OPTS += --disable-neon
endif
ifeq ($(BR2_MIPS_SOFT_FLOAT),y)
--
2.7.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [Buildroot] [PATCH 2/3] ffmpeg: explicitly disable NEON support
2016-08-10 21:29 ` [Buildroot] [PATCH 2/3] ffmpeg: explicitly disable NEON support Thomas Petazzoni
@ 2016-08-12 5:30 ` Khem Raj
2016-08-16 22:01 ` Peter Korsgaard
1 sibling, 0 replies; 7+ messages in thread
From: Khem Raj @ 2016-08-12 5:30 UTC (permalink / raw)
To: buildroot
> On Aug 10, 2016, at 2:29 PM, Thomas Petazzoni <thomas.petazzoni@free-electrons.com> wrote:
>
> When BR2_ARM_CPU_HAS_NEON=y, we pass --enable-neon. However, when
> BR2_ARM_CPU_HAS_NEON is disabled, we don't pass anything. This generally
> works fine, but turned out to integrate NEON code in ARMv7-M
> builds (since it's ARMv7, ffmpeg assumed it should enable NEON code).
>
> Even though ffmpeg is now disabled for ARMv7-M, it still makes sense to
> be explicit, and disable NEON support when the CPU doesn't have it.
Just an aside. You can add ?enable-thumb when the default ISA
chosen is thumb
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> ---
> package/ffmpeg/ffmpeg.mk | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/package/ffmpeg/ffmpeg.mk b/package/ffmpeg/ffmpeg.mk
> index c42336f..2b4219a 100644
> --- a/package/ffmpeg/ffmpeg.mk
> +++ b/package/ffmpeg/ffmpeg.mk
> @@ -437,6 +437,8 @@ FFMPEG_CONF_OPTS += --disable-vfp
> endif
> ifeq ($(BR2_ARM_CPU_HAS_NEON),y)
> FFMPEG_CONF_OPTS += --enable-neon
> +else
> +FFMPEG_CONF_OPTS += --disable-neon
> endif
>
> ifeq ($(BR2_MIPS_SOFT_FLOAT),y)
> --
> 2.7.4
>
> _______________________________________________
> buildroot mailing list
> buildroot at busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot
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^ permalink raw reply [flat|nested] 7+ messages in thread
* [Buildroot] [PATCH 2/3] ffmpeg: explicitly disable NEON support
2016-08-10 21:29 ` [Buildroot] [PATCH 2/3] ffmpeg: explicitly disable NEON support Thomas Petazzoni
2016-08-12 5:30 ` Khem Raj
@ 2016-08-16 22:01 ` Peter Korsgaard
1 sibling, 0 replies; 7+ messages in thread
From: Peter Korsgaard @ 2016-08-16 22:01 UTC (permalink / raw)
To: buildroot
>>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni@free-electrons.com> writes:
> When BR2_ARM_CPU_HAS_NEON=y, we pass --enable-neon. However, when
> BR2_ARM_CPU_HAS_NEON is disabled, we don't pass anything. This generally
> works fine, but turned out to integrate NEON code in ARMv7-M
> builds (since it's ARMv7, ffmpeg assumed it should enable NEON code).
> Even though ffmpeg is now disabled for ARMv7-M, it still makes sense to
> be explicit, and disable NEON support when the CPU doesn't have it.
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Committed, thanks.
--
Bye, Peter Korsgaard
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Buildroot] [PATCH 3/3] ffmpeg: don't pass --enable-mipsfpu on non-MIPS platform
2016-08-10 21:29 [Buildroot] [PATCH 1/3] ffmpeg: disable for ARMv7-M Thomas Petazzoni
2016-08-10 21:29 ` [Buildroot] [PATCH 2/3] ffmpeg: explicitly disable NEON support Thomas Petazzoni
@ 2016-08-10 21:29 ` Thomas Petazzoni
2016-08-16 22:02 ` Peter Korsgaard
2016-08-11 13:03 ` [Buildroot] [PATCH 1/3] ffmpeg: disable for ARMv7-M Thomas Petazzoni
2 siblings, 1 reply; 7+ messages in thread
From: Thomas Petazzoni @ 2016-08-10 21:29 UTC (permalink / raw)
To: buildroot
The current logic to pass the --{enable,disable}-mipsfpu option is:
ifeq ($(BR2_MIPS_SOFT_FLOAT),y)
FFMPEG_CONF_OPTS += --disable-mipsfpu
else
FFMPEG_CONF_OPTS += --enable-mipsfpu
endif
In practice, this means that on MIPS soft-float, --disable-mipsfpu is
passed, and that in *all* other cases, --enable-mipsfpu is passed,
including if we are *not* targetting the MIPS architecture.
Even though this doesn't seem to cause any problem, it is a bit weird to
see --enable-mipsfpu when you're building ffmpeg for a non-MIPS
architecture, so we better fix this by enclosing the MIPS-related
options in a MIPS condition.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
package/ffmpeg/ffmpeg.mk | 2 ++
1 file changed, 2 insertions(+)
diff --git a/package/ffmpeg/ffmpeg.mk b/package/ffmpeg/ffmpeg.mk
index 2b4219a..5a19617 100644
--- a/package/ffmpeg/ffmpeg.mk
+++ b/package/ffmpeg/ffmpeg.mk
@@ -441,6 +441,7 @@ else
FFMPEG_CONF_OPTS += --disable-neon
endif
+ifeq ($(BR2_mips)$(BR2_mipsel)$(BR2_mips64)$(BR2_mips64el),y)
ifeq ($(BR2_MIPS_SOFT_FLOAT),y)
FFMPEG_CONF_OPTS += --disable-mipsfpu
else
@@ -454,6 +455,7 @@ else
FFMPEG_CONF_OPTS += \
--disable-mips32r2
endif
+endif # MIPS
ifeq ($(BR2_POWERPC_CPU_HAS_ALTIVEC),y)
FFMPEG_CONF_OPTS += --enable-altivec
--
2.7.4
^ permalink raw reply related [flat|nested] 7+ messages in thread* [Buildroot] [PATCH 3/3] ffmpeg: don't pass --enable-mipsfpu on non-MIPS platform
2016-08-10 21:29 ` [Buildroot] [PATCH 3/3] ffmpeg: don't pass --enable-mipsfpu on non-MIPS platform Thomas Petazzoni
@ 2016-08-16 22:02 ` Peter Korsgaard
0 siblings, 0 replies; 7+ messages in thread
From: Peter Korsgaard @ 2016-08-16 22:02 UTC (permalink / raw)
To: buildroot
>>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni@free-electrons.com> writes:
> The current logic to pass the --{enable,disable}-mipsfpu option is:
> ifeq ($(BR2_MIPS_SOFT_FLOAT),y)
> FFMPEG_CONF_OPTS += --disable-mipsfpu
> else
> FFMPEG_CONF_OPTS += --enable-mipsfpu
> endif
> In practice, this means that on MIPS soft-float, --disable-mipsfpu is
> passed, and that in *all* other cases, --enable-mipsfpu is passed,
> including if we are *not* targetting the MIPS architecture.
> Even though this doesn't seem to cause any problem, it is a bit weird to
> see --enable-mipsfpu when you're building ffmpeg for a non-MIPS
> architecture, so we better fix this by enclosing the MIPS-related
> options in a MIPS condition.
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Committed, thanks.
--
Bye, Peter Korsgaard
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Buildroot] [PATCH 1/3] ffmpeg: disable for ARMv7-M
2016-08-10 21:29 [Buildroot] [PATCH 1/3] ffmpeg: disable for ARMv7-M Thomas Petazzoni
2016-08-10 21:29 ` [Buildroot] [PATCH 2/3] ffmpeg: explicitly disable NEON support Thomas Petazzoni
2016-08-10 21:29 ` [Buildroot] [PATCH 3/3] ffmpeg: don't pass --enable-mipsfpu on non-MIPS platform Thomas Petazzoni
@ 2016-08-11 13:03 ` Thomas Petazzoni
2 siblings, 0 replies; 7+ messages in thread
From: Thomas Petazzoni @ 2016-08-11 13:03 UTC (permalink / raw)
To: buildroot
Hello,
On Wed, 10 Aug 2016 23:29:02 +0200, Thomas Petazzoni wrote:
> In the ffmpeg code, libavutil/arm/asm.S makes some assumption about the
> ARM architecture for which the code is built. Only ARMv4, ARMv5, ARMv6
> and ARMv7-A is supported. Due to this, object files built out of
> ARM-optimized assembly code have the wrong architecture information,
> causing a failure at link time.
>
> Adding ARMv7-M support would be possible, but it doesn't exist yet in
> ffmpeg, and it's pretty unlikely that ffmpeg will ever be needed on an
> ARMv7-M platform, so this commit takes the simple approach of disabling
> ffmpeg for ARMv7-M.
>
> Fixes:
>
> http://autobuild.buildroot.net/results/ca4c67b093afd6f14349fcdc87b02e0480172e8c/
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> ---
> package/ffmpeg/Config.in | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
Applied to master, thanks.
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2016-08-16 22:02 UTC | newest]
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2016-08-10 21:29 [Buildroot] [PATCH 1/3] ffmpeg: disable for ARMv7-M Thomas Petazzoni
2016-08-10 21:29 ` [Buildroot] [PATCH 2/3] ffmpeg: explicitly disable NEON support Thomas Petazzoni
2016-08-12 5:30 ` Khem Raj
2016-08-16 22:01 ` Peter Korsgaard
2016-08-10 21:29 ` [Buildroot] [PATCH 3/3] ffmpeg: don't pass --enable-mipsfpu on non-MIPS platform Thomas Petazzoni
2016-08-16 22:02 ` Peter Korsgaard
2016-08-11 13:03 ` [Buildroot] [PATCH 1/3] ffmpeg: disable for ARMv7-M Thomas Petazzoni
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