[Intel-gfx] [RFC][PATCH 1/2] drm/i915: Don't increase the GPU frequency from the delayed VLV rps timer
Daniel Vetter
daniel at ffwll.ch
Wed Jun 26 12:21:31 CEST 2013
On Tue, Jun 25, 2013 at 11:53:28AM -0700, Jesse Barnes wrote:
> On Tue, 25 Jun 2013 21:38:10 +0300
> ville.syrjala at linux.intel.com wrote:
>
> > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> >
> > There's little point in increasing the GPU frequency from the delayed
> > rps work on VLV. Now when the GPU is idle, the GPU frequency actually
> > keeps dropping gradually until it hits the minimum, whereas previously
> > it just ping-ponged constantly between RPe and RPe-1.
> >
> > Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > ---
> > drivers/gpu/drm/i915/intel_pm.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > index 96cfb3e..eaf0fa2 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > @@ -3464,7 +3464,8 @@ static void vlv_rps_timer_work(struct work_struct *work)
> > * min freq available.
> > */
> > mutex_lock(&dev_priv->rps.hw_lock);
> > - valleyview_set_rps(dev_priv->dev, dev_priv->rps.rpe_delay);
> > + if (dev_priv->rps.cur_delay > dev_priv->rps.rpe_delay)
> > + valleyview_set_rps(dev_priv->dev, dev_priv->rps.rpe_delay);
> > mutex_unlock(&dev_priv->rps.hw_lock);
> > }
> >
>
> Hm that's not what I saw here; I stopped getting the timer interrupts
> when the GPU went idle. But that could be explained by punit fw
> differences.
>
> So this change looks ok to me.
>
> Reviewed-by: Jesse Barnes <jbarnes at virtuousgeek.org>
Queued for -next, thanks for the patch. In case you noodle around in here
some more, I'd also vote for a s/timer_work/delayed_work/ color change:
The execution enviroment of a time is _much_ different than from a work,
so sticking to consistent naming helps in reading code.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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