Re: [OE-core] RFC: pulseaudio vs. meson vs. neon

["Khem Raj" <raj.khem@gmail.com>]

On 6/28/21 11:20 AM, Andrea Adami wrote:
> On Mon, Jun 28, 2021 at 7:55 PM Khem Raj <raj.khem@gmail.com> wrote:
>>
>> Hi Andrea
>>
>> On 6/28/21 3:01 AM, Andrea Adami wrote:
>>> Hello,
>>>
>>> during a core-image-sato build for armv4 I got one single build
>>> failure with pulseaudio.
>>>
>>> This happens after commit 80bbea0 pulseaudio: switch build system from
>>> Autotools to Meson. In the commit text it is evidenced:
>>>
>>> "
>>> With Meson there's no option for disabling Neon optimizations if the
>>> compiler supports Neon. If -mfpu is set in CC or CFLAGS, it's ignored,
>>> because the build system adds -mfpu=neon at the end of the compiler
>>> command line, overriding any earlier -mfpu options. This shouldn't be
>>> a problem, because PulseAudio detects at runtime whether the CPU
>>> supports Neon instructions.
>>> "
>>>
>>> At the moment to build pulseaudio for armv4/5 I have reverted to using
>>> autotools.
>>>
>>>
>>> There was around a patch but has not been merged.
>>> https://lists.openembedded.org/g/openembedded-core/message/146375
>>>
>>
>> this patch is not right. It might let us compile but it will still emit
>> code that will expect VFP at runtime and hence fail to run.
>>
>>> Maybe a v2 will be accepted?
>>
>> right fix would be to add a proper neon support check in pulseaudio
>> meson'ary, and if PA has dropped the ball on non VFP ARM then it will be
>> hard to convince upstream to accept it but atleast you can try.
>>
> 
> Thank you for the review.
> I knew the patch was not right, I tried other workarounds and I
> failed. That's why the RFC was sent.
> 
> With my very limited knowledge about the matter it would be impossible
> for me to argue with L.P. upstream.
> My personal opinion is that the switch to meson was done too early, at
> least 14.x could have used autotools and less meson patches.
> 
> But if upstream deliberately breaks compatibility there isn't much we
> can do, maybe overpatching. sigh...
> 

I still hope that if we can add a proper neon detection patch to meson
they would be ok to accept it.


> Cheers
> A.A.
>>>
>>> Cheers
>>> A.A.
>>>
>>>
>>>
>>> 
>>>