[PATCH] drm/radeon/pm: autoswitch power state when in balanced mode

[Lucas Stach]

Am Montag, den 24.10.2016, 12:41 -0400 schrieb Alex Deucher:
> On Mon, Oct 24, 2016 at 5:46 AM, Christian König
> <christian.koenig at amd.com> wrote:
> > 
> > Am 23.10.2016 um 01:05 schrieb Lucas Stach:
> > > 
> > > 
> > > The current default of always using the performance power state
> > > leads
> > > to increased power consumption of mobile devices, which have a
> > > dedicated
> > > battery power state. Switch between the performance and battery
> > > power
> > > state automatically, dpending on the current AC power status,
> > > when the
> > > user asked for the balanced power state.
> > > 
> > > The user can still override this logic by asking for the
> > > performance
> > > or battery power state explicitly.
> > > 
> > > Signed-off-by: Lucas Stach <dev at lynxeye.de>
> > 
> > 
> > Nice addition, the only thing I can of hand see is that you
> > probably want to
> > remove the "balanced states don't exist at the moment" comment when
> > you
> > actually implement them (or abuse them).
> > 
> > Apart from that I'm not so deep into the PM stuff, so patch is only
> > Acked-by: Christian König <christian.koenig at amd.com>.
> 
> IIRC, I had a similar patch years ago, and it was generally shot down
> since it moved policy into the driver.  Also, certain userspace
> packages like tlp do this already.  That said, I'm happy to apply it
> if there are no objections.

I can relate to that argument. But as there is an explicit "battery"
power state that's a strong hint that the hardware is designed to use
this state when running on battery power. This patch does not add any
new policy, but merely changes the one already present in the kernel
(clearly always using the "performance" power state in balanced mode
already is a policy on its own).

Also this patch doesn't prevent userspace to implement a different
policy.

I don't care deeply enough to try to convince anyone if there is
objection to this patch, but I think driving the hardware in the
designed way by default without the user needing to install additional
tools is a good thing.

Regards,
Lucas