On Tue, Feb 14, 2012 at 21:17, Adam Jackson <ajax at redhat.com> wrote: > On 2/14/12 4:09 PM, Ben Widawsky wrote: > > The IOCTLs defined here may also be used with ppgtt (real ppgtt) but the >> interface may be insufficient for that. The contexts do provide a >> >> > A... what? > > Series looks reasonable to me. The one thing that makes me nervous is > 4/11 mentioning the BIOS, which honestly seems like an insane thing to let > your BIOS have _any_ say in, but then Intel sure does like to give the BIOS > a chance to make the OS less functional. The code in 7/11 effectively > limits things to between 4k and 1M; does that actually make sense? I can't > imagine wanting to allocate only 4k if it turns out we'd always need at > least (say) 32k. > > I have admittedly not read any of the docs on how this is meant to work, > apologies if that'd answer this. > The high-level overview of this feature is that it adds support for having a per-context set of GPU items the processes have access to. This is mostly important for GL_ARB_Robustness [1] and GL_EXT_Transform_feedback [2]. So what it does is adding a possibility of having a different context id for each set of operations. This way, what processes in one context_id do should not affect the processes in another set. For GL_ARB_Robustness, it could prevent one WebGL applications from taking down all the other users of the GPU for example; and for GL_EXT_Transform_feedback it would allow each process to have a way to store its own feedback data for different stages of the pipeline. And so on. As far as I know, it is also needed for full PPGTT support; but I don't know this part good enough to give more in-depth answer (Daniel?) (I hope it clarified the things a bit :)) [1] http://www.opengl.org/registry/specs/ARB/robustness.txt [2] http://www.opengl.org/registry/specs/EXT/transform_feedback.txt -- Eugeni Dodonov <http://eugeni.dodonov.net/> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.freedesktop.org/archives/intel-gfx/attachments/20120214/25ef1ee2/attachment.htm>
