On Tue, Mar 29, 2016 at 01:55:02PM +0200, Daniel Vetter wrote: > *Blonk* or whatever the sound for suddenly realization is. Totally forgot > that we're reuseding set_domain(GTT) for wc mmaps because this it's a nice > trick. > > Otoh, is that trick the reason why wc mmaps aren't coherent enough? One > possible difference is that this won't do the magic chipset flush in > intel-gtt.c that we have on gen3-5. Let's pretend wbinv doesn't exist on > gen2 ;-) But that's just an aside really ... No, writes through the *GTT* are not coherent. igt/gem_mmap_wc/coherency -> PASS igt/gem_mmap_gtt/coherency -> FAIL on byt/bsw Also see patch on list to insert a magic delay that fixes the issue exposed in the kernel (which causes various hangs and EINVALs). -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
