On 01/09/2014 10:03 PM, Eric Anholt wrote: > Eric Anholt <e...@anholt.net> writes: > >> Kenneth Graunke <kenn...@whitecape.org> writes: >> >>> The kernel doesn't even set up the aliasing PPGTT on Sandybridge, so any >>> writes marked as PPGTT will likely just get dropped on the floor. >> >> The hardware bug is that writes not marked as GTT are still looked up in >> the GTT anyway. >> >> The kernel does set up the PPGTT, which is how we found we needed to put >> in the kernel workaround based on DOMAIN_INSTRUCTION (of binding the >> target buffer to the gtt as well as the ppgtt, since the writes landed >> in the wrong place) >> >> I don't think this patch will change anything, but it seems reasonable >> if the commit message is updated. > > Actually, thinking about it more, I'd rather not explicitly use global > GTT, unless the function is also renamed to > gen6_emit_post_sync_nonzero_workaround, since now this function on > non-gen6 would reference GTT memory in its instruction, but the kernel > wouldn't put anything in the GTT. > > (I'd rather just leave the workaround as is, myself).
Okay, sounds like this is unnecessary. But...the next patch (helper function for writes) causes this to use PIPE_CONTROL_GLOBAL_GTT_WRITE on SNB only, and PPGTT on Gen7+. Part of the rationale for this patch was to change the SNB-specific behavior as a separate bisectable commit from the refactor. But I guess this patch does it universally, which is a bit different. I'm fine with dropping this patch. Is that what you'd like? _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
