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

[Eric Rannaud]

On Tue, Aug 26, 2014 at 4:06 AM, Ville Syrjälä
<ville.syrjala at linux.intel.com> wrote:
> FBC works best when the screen contents don't change. The more activity
> on the screen the less effective FBC becomes. 4W sounds way too much for
> FBC however. 0.4W is closer to what one might expect from FBC based on my
> observations. 4W sounds more like the difference between min vs. max
> display brightness to me.

That's why I'm here, because it is such a dramatic change. All
measurements were taken at constant brightness (4/100) and the
difference is indeed a full 4W, as reported by the battery (and seen
in: powertop(1),
/sys/bus/acpi/drivers/battery/PNP0C0A\:00/power_supply/BAT0/power_now,
and a noticeably faster drop in battery charge over time).

Could the FBC commit somehow also disable RC6, or similar?