Re: [RFC] Runtime display PM for VLV/BYT

Ville Syrjälä
2013-10-15T08:06:26Z

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.

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.

Or perhaps we just start with your stuff and Imre rebases his stuff on
top?

--
Ville Syrjälä
Intel OTC