[Intel-gfx] i915: Regression: +4W in idle power use on Macbook Pro 15 (late 2013)

[Eric Rannaud]

On Thu, Aug 28, 2014 at 9:41 AM, Sean V Kelley <sean.v.kelley at intel.com> wrote:
> For what it's worth, I have a Mid-2014, Macbook Pro Retina (13inch display),
> running Archlinux with 3.16.
>
> Definitely, enable_fbc is a win for me and I do manually enable it.  But I
> am still seeing what I believe to be
> a regression overall of about +4W even with fbc enabled.  Still digging for
> clues.

To be clear, because I don't think I listed that case, with
3.17.0-rc2-ARCH-00040-gff0c57ac7043 and i915.enable_fbc=1 the idle
power consumption goes back down to under 7W, which is about back to
normal.

There does seem to be a roughly +500mW regression since 3.13, but it's
a little hard to tell because of the sampling noise in the power
information as reported by powertop.

Is there a systematic, large-scale effort to obtain baseline power
data over time on various configs?