On Fri, 2015-10-02 at 14:45 +1000, Benjamin Herrenschmidt wrote: > On Fri, 2015-10-02 at 14:42 +1000, Dave Airlie wrote: > > I don't think we resolved this the last time we talked about it, > > > > but radeon writecombine maps fail hard on ppc, I think all the > > fixes > > either did something bad to AGP systems or weren't liked. > > > > My patch attached just fixes radeon, which is where I'm still > > seeing > > the issue. > > Yes, you MUST NOT set the flags of system memory to anything other > than > fully cachable on any cache coherent powerpc machine. This should be > bolted into the DRM core imho. > > _wc is only suitable for MMIO. Note that I wouldn't be surprised if we weren't the only arch like that. Playing with caching attributes of main memory smells from a system design and cache coherency protocol standpoint. x86 supports it but I wouldn't be surprised if some ARMs puke in interesting way as well. Cheers, Ben. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
