Created attachment 128845 [details]
dmesg output for 4.10.0-rc3 drm-tip
Under Linux 4.6 my Macbook Air spends > 60% in pc7 state. From Linux 4.7 the system only reaches pc2. Battery life suffers significantly because of this.
I previously reported this issue at https://bugzilla.kernel.org/show_bug.cgi?id=177151 but after discussion was told to go here.
I built drm-tip 9ea6a075c23ea914695d57944c0e74cff0c6bff4 and this still exhibits the problem. I have attached dmesg with debug output for this build.
I have done a git bisect and the results are:
git checkout ed4a6a7ca853253f9b86f3005d76345482a71283~ works.
git checkout ed4a6a7ca853253f9b86f3005d76345482a71283 exhibits the problem.
I run Debian Testing and have installed OS X El Capitan 10.11.6 on the Mac partition.
Model Name: MacBook Air (11-inch, Early 2014)
Model Identifier: MacBookAir6,1
Model Number: MD712X/B
(In reply to David Purton from comment #0)
> I have done a git bisect and the results are:
> git checkout ed4a6a7ca853253f9b86f3005d76345482a71283~ works.
> git checkout ed4a6a7ca853253f9b86f3005d76345482a71283 exhibits the problem.
The bad commit is
Author: Matt Roper <email@example.com>
Date: Tue Feb 23 17:20:13 2016 -0800
drm/i915: Add two-stage ILK-style watermark programming (v11)
Looks like a dupe of bug 96645
*** This bug has been marked as a duplicate of bug 96645 ***
I can confirm that the patch posted to bug 96645 fixes my problem. Thank you.