[Intel-gfx] [PATCH 4/4] drm/i915: make sure PC8 is enabled on suspend and disabled on resume

[Imre Deak]

On Mon, 2014-06-02 at 17:32 +0200, Daniel Vetter wrote:
> On Mon, Jun 02, 2014 at 02:37:35PM +0300, Imre Deak wrote:
> > On Mon, 2014-06-02 at 10:45 +0200, Daniel Vetter wrote:
> > > On Thu, May 29, 2014 at 02:11:37PM -0700, Jesse Barnes wrote:
> > > > From: Kristen Carlson Accardi <kristen at linux.intel.com>
> > > > 
> > > > This matches the runtime suspend paths and allows the system to enter
> > > > the lowest power mode at freeze time.
> > > > 
> > > > Signed-off-by: Kristen Carlson Accardi <kristen at linux.intel.com>
> > > > Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
> > > 
> > > pc8 is fully subsumed into runtime pm by now. Do we _really_ still need
> > > this?
> > 
> > Yes, since the system suspend/resume handlers are called with an RPM ref
> > held and thus PC8 disabled.
> 
> But doesn't patch 1 try to fix that?

That only disables the display side, but we won't disable PC8 until the
RPM suspend handler is called. And that won't happen because the last
RPM ref is held by the DPM framework for the duration of system
suspend/resume handlers.

> Imo we should have this here but instead go through highl-level the runtime
> pm functions to shut off the chip on all platforms.

After the planned refactoring we could have a low-level function that we
can call both from here and the runtime PM path, but until that happens
we need to do this here directly.

--Imre

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