On Mon, Oct 03, 2016 at 06:21:30PM -0700, Jason Ekstrand wrote: > On Mon, Oct 3, 2016 at 6:11 PM, Jason Ekstrand <ja...@jlekstrand.net> wrote: > > > On Tue, Sep 27, 2016 at 3:23 PM, Nanley Chery <nanleych...@gmail.com> > > wrote: > > > >> On Tue, Sep 27, 2016 at 03:12:17PM -0700, Chad Versace wrote: > >> > On Tue 27 Sep 2016, Nanley Chery wrote: > >> > > On Tue, Sep 27, 2016 at 11:00:21AM -0700, Chad Versace wrote: > >> > > >> > > > As a consequence of that reasoning, we should set > >> 3DSTATE_CLEAR_PARAMS.DepthClearValueValid = 1 > >> > > > whenever hiz is enabled, even if we don't care about the actual > >> clear value. > >> > > > > The logic seems to imply that we can't trust the context to save/restore > > our depth clear value so we have to set it every time. At the very least, > > once per batch? In any case, I doubt there's all that much cost involved > > in emitting 3DSTATE_CLEAR_PARAMS so I don't think re-emitting it is that > > big of a deal. > > > > Thinking about it a bit more... > > We only set up dept/stencil packets once per subpass and we only do clears > once per subpass so... I don't think we're actually saving anything by > emitting it at clear time rather than at depth/stencil setup time. It is a > bit more convenient because the clear values may be more accessible at > clear time. > > As far as "should we emit 3DSTATE_CLEAR_PARAMS all the time?" Let's not go > to any heroics to try and avoid re-emitting it. Once per subpass is not a > big deal at all. >
I wouldn't say the code to implement it was complex, but I'm fine with trading off efficiency for simplicity here. I'll add a comment describing the situation. -Nanley > --Jason > > > > > > > >> > > In the V3, I plan to emit that packet once at device initialization > >> time > >> > > HSW+, and to always emit it (in the expected location) for IVB/BYT. > >> Only > >> > > the latter platforms have the restriction that it must always be > >> > > programmed with the other depth/stencil commands. > >> > > >> > Is there any benefit to emitting it multiple times on ivb/byt? Does > >> > emitting once during initialization, as for hsw, also work for ivb/byt? > >> > If so, the code is cleaner if the two gens share the same workaround > >> > code. > >> > >> The benefit for emitting it multiple times on IVB/BYT is that we're > >> (possibly) following the oddly-worded programming note for the packet: > >> > >> From the IVB PRM Vol2P1, 11.5.5.4 3DSTATE_CLEAR_PARAMS: > >> > >> 3DSTATE_CLEAR_PARAMS must always be programmed in the along with > >> the other Depth/Stencil state commands(i.e. 3DSTATE_DEPTH_BUFFER, > >> 3DSTATE_STENCIL_BUFFER, or 3DSTATE_HIER_DEPTH_BUFFER) > >> > >> HSW+ doesn't have this restriction, so we're free to only do it once. > >> > > > > _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
