Comment # 3
on bug 93264
from Nicolai Hähnle
Time to document some information I've gathered. I can now confirm that Mesa has nothing to do with it. Something must have gone wrong with my builds initially, sorry for having caused confusion. I captured an apitrace for better reproducibility[0] and ran it with shader dumps enabled and flushing after each draw call in the "interesting" region. I am going to attach the R600_DEBUG=check_vm dump which I've cross-referenced with R600_DEBUG=vm to obtain the shaders that were active during the draw call (file names with prefix llvm-c0a189c.mesa-caf12bebd). I then matched the shaders to those dumped by a run with a good version of LLVM (commit just before the bad one, file names with prefix llvm-26ddca1.mesa-caf12bebd). Clearly, the LLVM changes caused some significant re-ordering of the instruction schedule, and that somehow, surprisingly, seems to be responsible for the VM faults. Another aspect to note is that the shaders are compiled before draw call 174000, while the VM faults happen shortly after draw call 178000. This seems to suggest that the shaders alone only cause VM faults in conjunction with some other state. However, the VM faults have always happened in exactly the same point so far, so it does appear to be deterministic. [0] The demo always causes VM faults, so I'm not going to upload the giant trace; however, the timing varies between runs, so it's cleaner to reproduce using a trace.
You are receiving this mail because:
- You are the assignee for the bug.
_______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
