[Intel-gfx] [PATCH i-g-t v2] lib/igt_pm: Restore runtime pm state on test exit

[Chris Wilson]

Quoting Tvrtko Ursulin (2018-02-28 15:35:06)
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> Some tests (the ones which call igt_setup_runtime_pm and
> igt_pm_enable_audio_runtime_pm) change default system configuration and
> never restore it.
> 
> The configured runtime suspend is aggressive and may influence behaviour
> of subsequent tests, so it is better to restore to previous values on test
> exit.
> 
> This way system behaviour, with regards to a random sequence of executed
> tests, will be more consistent from one run to another.
> 
> v2: Read failure means no runtime pm support so don't assert on it.
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Imre Deak <imre.deak at intel.com>
> Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk> # v1
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris