Bug#572420: Please change this bug to libsdl1.2debian

[Michel Dänzer]

On Sun, 2010-04-04 at 00:14 +0100, peter green wrote: 
> peter green wrote:
> > >The bug is actually in libsdl1.2debian. It has improper compile flags
> > >for powerpc g3. What these are I do not know.
> > looking at the build log -maltivec seems to be the smoking gun. It 
> > appears the upstream configure script is looking for altivec support 
> > at build time and enabling it if it detects it (which is the right 
> > thing to do when building for your own system but the WRONG thing to 
> > do when building distribution packages)
> >
> > Ideally this sort of issue needs access to ppc hardware both with and 
> > without altivec to nail it down (you need to do the builds on machines 
> > with altivec support and then check they work on machines without it) 
> > . I'll try to take a look using qemu but I can't promise anything.
> I've come up with a patch which I beleive should fix this but building 
> with qemu is extremely slow and in any case to properly test this really 
> needs hardware both with (to do the build) and without (to test it) 
> altivec to properly test.

Can the problem be worked around by running the affected apps with the
environment variable SDL_ALTIVEC_BLIT_FEATURES=0?

If yes, SDL_HasAltiVec() may just incorrectly return true on
non-Altivec-capable systems.

If no, apparently the Altivec specific code isn't separated enough yet
in the SDL build / packaging. Should be solvable either by moving all
the Altivec specific code to separate .c files and only setting the
Altivec specific compiler flags for those, or by building the binaries
once with and without Altivec support each and installing the Altivec
enabled binaries in /usr/lib/altivec/.


-- 
Earthling Michel Dänzer           |                http://www.vmware.com
Libre software enthusiast         |          Debian, X and DRI developer