[Intel-gfx] [PATCH 2/9] drm/i915/gt: Fix up clock frequency

[Chris Wilson]

Quoting Andi Shyti (2020-04-27 20:52:47)
> Hi Chris,
> 
> On Mon, Apr 27, 2020 at 09:54:01AM +0100, Chris Wilson wrote:
> > The bspec lists both the clock frequency and the effective interval. The
> > interval corresponds to observed behaviour, so adjust the frequency to
> > match.
> 
> what is the observed behavior?

The PM intervals are 1280ns for older HW, not 640ns as implied by the
25MHz clock. Wrote a selftest to measure the PM ticks and confirmed the
intervals are correct, the frequency isn't.
-Chris