[Intel-gfx] [RFC] Runtime display PM for VLV/BYT
imre.deak at intel.com
Tue Oct 15 14:16:11 CEST 2013
On Tue, 2013-10-15 at 11:06 +0300, Ville Syrjälä wrote:
> On Mon, Oct 14, 2013 at 04:07:44PM -0700, Jesse Barnes wrote:
> > This set adds bits needed for runtime power support, currently only
> > lightly tested on VLV/BYT:
> > 1) suspend/resume callbacks for different platforms
> > 2) save/restore of display state across a power well toggle
> > 3) get/put of display power well in critical places
> > The TODO list still has a few items on it, and I'm looking for feedback:
> > 1) sprinkle around some power well WARNs so we can catch things easily
> > 2) add some tests using DPMS and NULL mode sets and comparing power
> > well state
> > 3) better debugfs support for multiple wells
> > 4) refcount of power well in debugfs (with ref holders?)
> > 5) more testing - I think the load time ref is still busted here and
> > on HSW
> > 6) convert HSW as well so DPMS will shut things down, not just mode
> > sets
> > Thoughts or comments?
> I'd also like to see what Imre cooked up, and then come up with some
> grand unified design. Based on our discussions I think his power well
> abstraction sounded somewhat nicer and more general.
I've pushed what I have so far to:
I've tested this on VLV with VGA output so far and somewhat on HSW. I'd
still have to check the need to do any HW state save/restore and the GFX
clock forcing, afaics Jesse has already code for these in his patchset.
> Also your locking seems to be fubar in places (frobbing with sideband
> while holding a spinlock). I think Imre converted the power wells to
> use a mutex everywhere.
Yea, I solved that by changing power_well->lock to be a mutex.
> Or perhaps we just start with your stuff and Imre rebases his stuff on
That works for me too. In any case would be nice to get some feedback
especially from Paulo as my changes are mostly about the current power
domain / well handling parts.
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