[FFmpeg-devel] [PATCH] Fix configure to disable MMX for Pentium Pro

Alex Converse alex.converse
Thu Aug 26 19:37:06 CEST 2010


On Thu, Aug 26, 2010 at 1:10 PM, avcoder <ffmpeg at gmail.com> wrote:
> On Thu, Aug 26, 2010 at 10:48 PM, Jason Garrett-Glaser <
> darkshikari at gmail.com> wrote:
>>
>> >
>> > The main point of the change was to get rid of the stupid global
>> > mm_flags variable. ?We discussed it at length some time ago (it nearly
>> > went full bikeshed), and nobody objected then, not even the distro
>> people.
>> > Why the sudden outrage?
>>
>> Whether we like it or not, a huge number of people compile ffmpeg with
>> --cpu=i686 or similar for generic builds. ?With these changes,
>> --cpu=i686 will actually SLOW DOWN ffmpeg as opposed to not specifying
>> CPU at all. ?This is not intuitive behavior.
>>
>>
> ?+1
>
> I love i686 for generic P6 architectures which support MMX.
>

i686 isn't required to have MMX,

consider --cpu=pentium2

We dropped runtime detection from for MMX support.

> We should revert r24946: ?Disable MMX for i686 and pentiumpro
>

If something should be reverted it is dropping runtime detection for MMX



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