[Intel-gfx] [PATCH 7/9] drm/i915: allow package C8+ states on Haswell (disabled)

[Chris Wilson]

On Wed, Aug 07, 2013 at 10:38:19AM -0300, Paulo Zanoni wrote:
> 2013/8/6 Chris Wilson <chris at chris-wilson.co.uk>:
> > On Tue, Aug 06, 2013 at 06:57:17PM -0300, Paulo Zanoni wrote:
> >> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> >> index 2ef4335..7f6ec9e 100644
> >> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> >> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> >> @@ -1590,6 +1590,8 @@ void intel_ring_advance(struct intel_ring_buffer *ring)
> >>  {
> >>       struct drm_i915_private *dev_priv = ring->dev->dev_private;
> >>
> >> +     hsw_package_c8_gpu_busy(dev_priv);
> >> +
> >
> > Ahem, what is this doing here? If only we had something that was the
> > opposite of intel_mark_idle... At this point, I am going to get some
> > sleep...
> 
> You're suggesting me to use intel_mark_busy? I have to admit I saw it,
> but I noticed intel_mark_busy is called after intel_ring_advance, and
> I was trying to follow what Ben suggested me. If you're suggesting
> this, I guess it's ok, so I will test this possibility.

intel_mark_busy() is where we note the transition in userspace activity,
it should be where we put all the little hooks and pm tweaks required.
If you however need the pc8 disable earlier than the ring register write,
we should do it in intel_ring_begin(). Ultimately, though we should be
able to squash it into a single operation such that we never submit a
command before intel_mark_busy(). Hmm, easier in fact just to move
intel_mark_busy() to intel_ring_begin() and I think everybody is happy.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre