[Intel-gfx] [PATCH] drm/i915/ringbuffer: Reload PDs harder on byt/bcs

[Chris Wilson]

Quoting Chris Wilson (2018-09-10 14:08:08)
> Baytrail takes a little more convincing that it needs to actually reload
> its Page Directoy (ppGTT) before the context switch, so repeat it until
> it gets the message. Once again the arbitrary values here are
> empirically derived.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=107861
> Testcase: igt/gem_exec_parallel/fds
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

On drm-tip, this testcase fails within 15 iterations (30s). It has now
survived 24 hours. I think it've proved itself against this one testcase
and deserves a shot at the rest.
-Chris