https://bugs.freedesktop.org/show_bug.cgi?id=84662
--- Comment #18 from Andy Furniss adf.lists@gmail.com --- (In reply to Andy Furniss from comment #14)
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.
I haven't tried the patch yet. will do but I got some strange results last thing yesterday which will make me hesitant about declaring any patch good or bad.
I started resetting around in mesa and noticed unexpected goods - so I tried head and got a good noth with and without 1st patch.
Rebooted into 3.17-rc7 still good.
Did some recompiling of llvm/mesa as I had changed my normal setup slightly - got bad.
Repeated resetting mesa to older + patch got good, reset to head again, bad. Applied patch on head good, reversed patch on head - still good.
I am wondering at this time whether card is in some nice state so power cycle - still good. Boot into 3.18 still good, clean & recompile the same mesa without doing anything else - bad again. Still bad after power cycles.
I always make distclean + git clean -dfx when doing anything other than applying or reversing a patch.
So it seems that there is some randomness whether I am good or bad between mesa build/installs.
This does not however tally with my kernel bisect which seemed to go flawlessly.
I assume there is no card state that can survive power off.
So currently a bit confused - as reported by Christoph in the other bug, it is possible to have good with vanilla mesa/kernel, but apparently for me the "same" mesa can also be bad.
I did try more clean/rebuild cycles including single thread but am currently still bad.