https://bugs.freedesktop.org/show_bug.cgi?id=84662
--- Comment #14 from Andy Furniss adf.lists@gmail.com --- (In reply to Michel Dänzer from comment #12)
Created attachment 107391 [details] [review] Make Mesa behave as if the kernel was older
(In reply to Andy Furniss from comment #3)
gallium hud on bad showing different vram gtt usage
That's very interesting indeed — on the 'good' screenshot, requested and actual VRAM usage match up almost perfectly, but on the 'bad' one, there's a large discrepancy.
With a current kernel, does the bad behaviour start with the same Mesa commit as the Unigine stutters?
The attached patch makes Mesa behave the same with current kernels as it does with older ones which don't have the bisected commit. Does that avoid the problem?
More testing - incomplete but will post initial findings as I don't know when I'll finish.
I managed to get older mesa to build with new llvm by applying the build fixes.
With mesa on the commit before r600g,radeonsi: Set RADEON_GEM_NO_CPU_ACCESS flag for tiled BOs (I don't know yet exactly what mesa commit changed things)
I can with your patch or the stream revert get "good" behavior, this was with a kernel on the "bad" HPD kernel commit.
Will test more over time.