Should be fixed:

commit 1f7b847d72c3583df5048d83bd945d0c2c524c28
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Wed Feb 8 14:30:33 2017 +0000

    drm/i915: Disable engine->irq_tasklet around resets
    
    When we restart the engines, and we have active requests, a request on
    the first engine may complete and queue a request to the second engine
    before we try to restart the second engine. That queueing of the
    request may race with the engine to restart, and so may corrupt the
    current state. Disabling the engine->irq_tasklet prevents the two paths
    from writing into ELSP simultaneously (and modifyin the execlists_port[]
    at the same time).
    
    Fixes: 821ed7df6e2a ("drm/i915: Update reset path to fix incomplete requests
")
    Testcase: igt/gem_exec_fence/await-hang
    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
    Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
    Cc: Mika Kuoppala <mika.kuoppala@intel.com>
    Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
    Link: http://patchwork.freedesktop.org/patch/msgid/20170208143033.11651-3-ch
ris@chris-wilson.co.uk

This bug was about APL but was fix general all platforms?
for this igt@gem_exec_fence@await-hang-default test?

For this bug, it is common to execlists.

Do you consider all of these to be closed?
FDO#99733
FDO#99726
FDO#99725
FDO#99729

For this test: igt@gem_exec_fence@await-hang-default I mean.

bug 99726 is unresolved, on hsw so not this patch (this patch is execlists only), and there's not enough information there to ascertain the cause.

bug 99725 is a mismash, of which the await-hang-default fail might be this but an invisible link.

bug 99733 had a different root cause, should be fixed by the patch given there.