[Intel-gfx] [PATCH] drm/i915: Grab RPM wakeref around enabling vblank interrupts

[Chris Wilson]

On Fri, Oct 07, 2016 at 09:44:53PM +0300, Ville Syrjälä wrote:
> On Fri, Oct 07, 2016 at 07:33:00PM +0100, Chris Wilson wrote:
> > On Fri, Oct 07, 2016 at 09:06:07PM +0300, Ville Syrjälä wrote:
> > > On Fri, Oct 07, 2016 at 02:50:32PM +0100, Chris Wilson wrote:
> > > > Whilst the vblank is configured to send an interrupt everytime, we need
> > > > to keep the device awake to process those interrupts.
> > > 
> > > If we can enable vblanks the pipe will be active, and thus we can't
> > > runtime suspend anyway. Also might_sleep() would be a problem.
> > 
> > Where is the pipe made active? Is it just having any mode is sufficient
> > to disable rpm? Will that always be the case?
> 
> Active pipe holds a power domain reference, which implies an rpm
> reference as well.

What's the best way to write

	/* vblank IRQ requires the powerwell to stay awake */
	WARN_ON(!to_intel_crtc(dev_priv->pipe_to_crtc_mapping[pipe])->active);

?

-- 
Chris Wilson, Intel Open Source Technology Centre