[Intel-gfx] [PATCH] drm/i915: Reduce nested prepare_remote_context() to a trylock

[Chris Wilson]

Quoting Chris Wilson (2019-11-26 06:55:21)
> On context retiring, we may invoke the kernel_context to unpin this
> context. Elsewhere, we may use the kernel_context to modify this
> context. This currently leads to an AB-BA lock inversion, so we need to
> back-off from the contended lock, and repeat.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111732
Fixes: a9877da2d629 ("drm/i915/oa: Reconfigure contexts on the fly")
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris