[Intel-gfx] [PATCH v7 1/2] drm/i915: remove broken i915_sseu_status interface

[Lionel Landwerlin]

On 08/04/2020 14:55, Andi Shyti wrote:
> Hi Tvrtko,
>
> I start by saying that this patch was mainly sent to kickstart a
> discussion about cleanups required in debugfs and how debugfs can
> be inconsistent and how much it looks to me that we are relying
> on its current state.
>
>>> The i915_sseu_status is broken and the tests on this interface
>>> are disabled. There is no reason to drag it along.
>> Not saying we need it, but can you say how it is broken?
> well tests in igt are failing because we don't get the results we
> expect, I don't know where it is actually broken but the igt test
> looks straight forward to me.
>
> I assume (with some hints I received, though) that the sseu
> reads are inconsistent.
>
> Andi

I think it's broken because we're reading an acknowledgement registers.

These registers seems to be populated only after a context is run.

If you read it before a context is run after coming out of power 
management, there is no request to acknowledge and you get 0 values.


-Lionel