Created attachment 99813 [details]
dmesg of eglgears_screen with drm-fixes 3.15-rc6 and agd5f's use-old-hdp-flush
patch

(In reply to comment #58)
> Created attachment 99594 [details] [review] [review]
> use old hdp flush
> 
> Does this kernel patch help?

I don't know if this info helps, but anyway:

With current stuff (llvm, glamor, mesa from git) and airlied's current
drm-fixes (commit 77c01bef72a5ce5cb24adae6066ed81a52004d30) with your
old-hdp-flush patch and the patch from bug 74250, I get:
* eglinfo works multiple times in a row
* egltri_screen from mesa-demos works, outputs a coloured triangle on grey
background for 5s (with 3 monitors attached)
* eglgears_screen garbles the screen, but it only stalls the gpu once or twice
(dmesg attached) and then returns to console
* and I can repeatedly run egltri_screen even after eglgears_screen ran

So for me it seems like quite an improvement.

I'd like to help further if possible, but I don't have any experience with gdb
unfortunately. If I can do anything else or if there are some detailed
instructions on what to do, just tell me and I'll try to find some time.