On 10/21/2013 08:40 AM, Ian Romanick wrote: > On 10/17/2013 11:09 PM, Kenneth Graunke wrote: >> Here's my implementation of ARB_transform_feedback2. I believe it's >> complete; it passes all of our Piglit tests and a lot of Intel's >> oglconform tests. >> >> This should work out of the box on Ivybridge and Baytrail. It won't >> work on Haswell at the moment, due to restrictions on register writes >> (to be solved in a future kernel version). Patch 9 will need to be >> replaced with something that detects whether or not we can write >> registers from userspace batchbuffers. >> >> In the meantime, I figured I'd send out the rest for review. >> >> Porting this back to Sandybridge is probably doable, but annoying. >> Sandybridge doesn't have the MI_LOAD_REGISTER_MEM command, so we'd have >> to map the buffers and use MI_LOAD_REGISTER_IMM. Seems pretty gross. >> Plus, transform feedback is done very differently pre-Ivybridge. I'm >> not sure it's worth it, seeing as it's a GL 4.0 feature. > > I assume this is just to support glDrawTransformFeedback?
No, it's to support glResumeTransformFeedback. glDrawTransformFeedback actually just reads pipeline statistics counters and leaves them free-running. > Can you add that information to http://dri.freedesktop.org/wiki/I965Todo/ ? Actually, I'm probably wrong...on Gen7 we use MI_LOAD_REGISTER_MEM to copy offsets into the SO_WRITE_OFFSET(n) registers. But on Sandybridge, XFB is done using the geometry shader, so it works entirely differently. I don't think there is a register to load. I'll just let whoever looks into it figure it out. Not much insight anyway. --Ken _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
