commit 0a393229479d61829a2f8671c1a46f533c76b385 (HEAD, upstream/master)
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Tue Mar 27 14:44:30 2018 +0100

    igt/gem_ctx_isolation: Reset a scratch context
    
    If we inject a reset into the target context, there is a risk that the
    register state is never saved back to memory. The exact interaction
    between reset, the context image and the precise timing of our execution
    are not well defined. Since we cannot ensure that the context image
    remains valid, force a context switch prior to the reset.
    
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105270
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105457
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105545
    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
    Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
    Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
    Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

I will close this, the machine has been re-named to fi-cfl-s3 so I can't get data showing that the fix worked.