On Tue, 18 Aug 2009 12:10:34 -0700 Keith Whitwell <kei...@vmware.com> wrote:
> This seems wrong to me -- the client doesn't need to sleep - all it's > going to do is build a command buffer targeting the new backbuffer. > There's no problem with that, it should be the preserve of the GPU > scheduler (TTM or GEM) to ensure those commands (once submitted) > don't get executed until the buffer is available - otherwise you're > potentially pausing your application for no good reason. The app > should be throttled if it gets more than a couple of frames ahead, > but there should be 100% overlap with hardware otherwise. I think this is possible with the current scheme if you return a "flip complete" event immediately, or structure your DDX driver to indicate completion early. That would mean tracking busy (i.e. flip pending) buffers in your scheduler (I think I had it hooked into GEM at one point, but with the generic code it's not needed), but it's definitely possible as Thomas described. And I agree you want to keep the GPU fed with commands (that it can actually execute!) as much as possible; that's especially important for low end chips. > If you need a solution that doesn't rely on the buffer manager, > perhaps resort to triple-buffering, or else create a new buffer and > return that in DRI2GetBuffers (and let the scanout one be freed once > the flip is done). Yeah, that's another good option; should be fairly trivial with this codebase (the next DRI2GetBuffers call would just come back immediately with new buffers). > It seems like arbitrating command execution against on-hardware > buffers should be the preserve of the kernel memory manager & other > actors shouldn't be double-guessing that. Right, but the main thing here is to avoid here is putting the whole server to sleep. Anyway, to me this discussion is more of a "future directions" one than a blocker for this particular patchset. AFAICT the only thing that needs fixing with this patch is my lock confusion (struct_mutex vs mode_config). Or would you like something substantial changed with these bits before they land? -- Jesse Barnes, Intel Open Source Technology Center ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
