<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Mon, Mar 26, 2018 at 6:39 PM, Erico Nunes <<a href="mailto:nunes.erico@gmail.com" target="_blank">nunes.erico@gmail.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Thanks all for the input. I don't have an in-depth knowledge of the hardware either, though as far as we can see the hardware does expect that we pass min_index in the command stream. max_index is used to calculate the sizes in other command stream fields (which is not the same as pipe_draw_info.count). The existing lima-ng implementation does the same: <a href="https://github.com/limadriver-ng/lima/blob/660a940c8cc151fd886559233c1a22385ee5f254/limare/lib/gp.c#L584 (draw-" rel="noreferrer" target="_blank">https://github.com/limadriver-ng/lima/blob/660a940c8cc151fd886559233c1a22385ee5f254/limare/lib/gp.c#L584 (draw-</a>>vertex_start). On Sat, Mar 17, 2018 at 7:23 PM, Ilia Mirkin <<a href="mailto:imirkin@alum.mit.edu">imirkin@alum.mit.edu</a>> wrote: > For an approximation, you can use the sizes of the bound vbo's to > guess a min/max index. See > <a href="https://cgit.freedesktop.org/mesa/mesa/tree/src/gallium/drivers/vc4/vc4_draw.c#n183" rel="noreferrer" target="_blank">https://cgit.freedesktop.org/mesa/mesa/tree/src/gallium/drivers/vc4/vc4_draw.c#n183</a> > for an example. I quickly played with porting something like that to mesa-lima but I don't think it can solve our problem. Apparently our bo currently have a fairly large fixed size so I'm not sure we can do an equivalent calculation using bo size. And then, min_index is required too. On Sat, Mar 24, 2018 at 10:32 PM, Marek Olšák <<a href="mailto:maraeo@gmail.com">maraeo@gmail.com</a>> wrote: > Here is how to do it: > > if (max_index != ~0u) > // index bounds are valid; > else > // scan the index buffer manually; > > u_vbuf_get_minmax_index can be used for the scanning. mesa-lima currently does not use any vbuf function. And we currently can't call u_vbuf_get_minmax_index since it's static in u_vbuf.c. I suppose we can consider making u_vbuf_get_minmax_index public then. I tested this and it works for me. It's still a bit annoying since we need to create fields probably in lima_context (like vc4_context.max_index does) and use those instead of the ones in pipe_draw_info. But not a big problem I guess. We could submit this refactor when mesa-lima gets proposed upstream. Just for completeness, one other idea that came up was to define a new PIPE_CAP_xxx config used to override st_context.draw_needs_minmax_index, and set that in this driver. This way, pipe_draw_info would come correctly filled and we wouldn't need to explicitly assemble minmax indices during the driver draw_vbo. How does this sound compared to the other solution? </blockquote></div> </div><div class="gmail_extra">The PIPE_CAP solution sounds OK. </div><div class="gmail_extra"> </div><div class="gmail_extra">Marek </div></div>