[PATCH 9/9] drm/ttm: Sanity check mapping attributes on powerpc in ttm_io_prot()

[Benjamin Herrenschmidt]

On Thu, 2014-09-04 at 16:52 +0900, Michel Dänzer wrote:
> >   #endif
> > +#if defined(__powerpc__) && !defined(CONFIG_NOT_COHERENT_CACHE)
> > +     /*
> > +      * Using a non-cachable mapping of system memory on
> > +      * cache coherent powerpc's can be fatal, let's make
> > +      * sure this doesn't happen and warn if it does. The
> > +      * only exception is powermac with AGP which has to
> > +      * take the risk.
> > +      */
> > +     if (!machine_is(powermac) &&
> > +         ((caching_flags & TTM_PL_FLAG_SYSTEM) ||
> > +          (caching_flags & TTM_PL_FLAG_TT))) {
> > +             pr_err_once("TTM: Attempt to use a non-cached"
> > +                         " mapping on RAM unsupported !\n");
> > +             return tmp;
> 
> NAK, this breaks AGP on PowerMacs.

No it doesn't :-)

Cheers,
Ben.