Re: [PATCH 0/1] Change default for cortexa* to armv7at-neon.

[Martin Jansa <martin.jansa@gmail.com>]

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On Fri, Aug 22, 2014 at 05:06:26PM -0500, Peter Seebach wrote:
> On Fri, 22 Aug 2014 23:46:26 +0200
> Martin Jansa <martin.jansa@gmail.com> wrote:
> 
> > changing
> > default DEFAULTTUNE (and TUNE_PKGARCH with that) to have thumb while
> > still building with -marm doesn't make much sense to me and is only
> > confusing.
> 
> I think the distinction is that if you use armv7at-neon, you *can* build
> specific packages with thumb. Mostly, I guess, I don't think it makes sense
> to use a tuning that specifically states that it can't run thumb code for
> processors which can. Although... May not be an important distinction, really,
> as you note.

> I don't think it makes sense to use a tuning that specifically states
> that it can't run thumb code

The problem is that "t" in DEFAULTUNE always adds "t2" to TUNE_PKGARCH
no matter if you've built the package with -marm or -mthumb. So as long
as ARM_INSTRUCTION_SET is "arm" by default, we should use the same
default for DEFAULTTUNE - I wouldn't mind changing ARM_INSTRUCTION_SET
at least more people will be hit by those ICEs I've reported earlier
(with patch forcing ARM_INSTRUCTION_SET to "arm" for gdb and icu
"gdb: force arm mode" http://patchwork.openembedded.org/patch/75703/
"icu: force arm mode" http://patchwork.openembedded.org/patch/75817/

It would be interesting to try
http://patchwork.openembedded.org/patch/70985/
with latest master to see if it can work correctly now, then I wouldn't
be so opposed to "enabling" thumb in DEFAULTTUNE (even without
ARM_INSTRUCTION_SET change)

> > Every distro can use something more "optimized" DEFAULTTUNEs for each
> > MACHINE they use, I do it for SHR:
> > https://github.com/shr-distribution/meta-smartphone/blob/shr/meta-shr-distro/conf/distro/include/defaulttunes.inc
> 
> Huh, that's an interesting point. I'll wave this at people and see what they
> think of it.
> 
> -s
> -- 
> Listen, get this.  Nobody with a good compiler needs to be justified.

-- 
Martin 'JaMa' Jansa     jabber: Martin.Jansa@gmail.com

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