[Intel-gfx] [PATCH 21/21] drm/i915/slpc: Fail intel_runtime_suspend if SLPC or RPS not active

[Chris Wilson]

On Thu, Apr 28, 2016 at 10:57:20AM +0300, Imre Deak wrote:
> On to, 2016-04-28 at 07:56 +0100, Chris Wilson wrote:
> > On Wed, Apr 27, 2016 at 06:11:05PM -0700, tom.orourke at intel.com wrote:
> > > From: Sagar Arun Kamble <sagar.a.kamble at intel.com>
> > > 
> > > intel_runtime_suspend failed with warning if RPS was disabled.
> > > With SLPC enabled, RPS is disabled. With SLPC, warning is now changed
> > > to consider SLPC active status as well. This will ensure runtime suspend
> > > proceeds when SLPC enabled.
> > > 
> > > v2: Commit message update. (Tom)
> > > 
> > > Signed-off-by: Sagar Arun Kamble <sagar.a.kamble at intel.com>
> > > Signed-off-by: Tom O'Rourke <Tom.O'Rourke at intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/i915_drv.c | 3 ++-
> > >  1 file changed, 2 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> > > index cc22fa0..00a2713 100644
> > > --- a/drivers/gpu/drm/i915/i915_drv.c
> > > +++ b/drivers/gpu/drm/i915/i915_drv.c
> > > @@ -1474,7 +1474,8 @@ static int intel_runtime_suspend(struct device *device)
> > >  	struct drm_i915_private *dev_priv = dev->dev_private;
> > >  	int ret;
> > >  
> > > -	if (WARN_ON_ONCE(!(dev_priv->rps.enabled && intel_enable_rc6(dev))))
> > > +	if (WARN_ON_ONCE(!((dev_priv->rps.enabled || intel_slpc_active(dev)) &&
> > > +			   intel_enable_rc6(dev))))
> > 
> > The real question here is why does runtime suspend depend on either of
> > these being enabled (espcially rps!).
> 
> We need RC6 enabled across a runtime suspend/resume since we depend on
> the RC6 context to be retained across these transitions. There is no
> separate knob for RPS and we enable RC6 and RPS together, that's why
> rps.enabled is checked.

So, from the standpoint of this series, we should be separating the two
and giving rc6 its own bit of bookkeeping.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre