Why Ubuntu 15.04 with kernel 3.19.0-15 is using significantly more power?

Question

I've recently upgraded to 15.04 and immediately noticed significantly faster battery depletion and warmer case. My MacBook Air 6,2 would easily hold 10-12 hours on battery power with Ubuntu 14.10 and now it only holds 3 hours(!) I've tried using tlp, removing powerclamp (I noticed 4 x kidle_inject) and playing with other parameters. The current workaround is booting with the older and better 3.16.0-36.

Does anyone else experiencing the same? Anyone knows how to solve this? I can provide any information and will try anything to solve this.

EDIT: Per a request in the comments, this is the same with both kernels:

$ cat /proc/cpuinfo | grep "model name"
model name  : Intel(R) Core(TM) i7-4650U CPU @ 1.70GHz
model name  : Intel(R) Core(TM) i7-4650U CPU @ 1.70GHz
model name  : Intel(R) Core(TM) i7-4650U CPU @ 1.70GHz
model name  : Intel(R) Core(TM) i7-4650U CPU @ 1.70GHz
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver
intel_pstate
$ cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
powersave

EDIT 2: sudo turbostat -S sleep 300

With 3.16.0-36:
Avg_MHz   %Busy Bzy_MHz TSC_MHz     SMI  CPU%c1  CPU%c3  CPU%c6  CPU%c7 CoreTmp  PkgTmp Pkg%pc2 Pkg%pc3 Pkg%pc6 Pkg%pc7 Pkg%pc8 Pkg%pc9 Pk%pc10 PkgWatt CorWatt GFXWatt
      82    4.85    1689    2299       0   10.08    1.91    0.93   82.23      52      52   20.91    2.16    6.80   45.68    0.00    0.00    0.00    2.07    0.43    0.07

With 3.19.0-15:
 Avg_MHz   %Busy Bzy_MHz TSC_MHz     SMI  CPU%c1  CPU%c3  CPU%c6  CPU%c7 CoreTmp  PkgTmp Pkg%pc2 Pkg%pc3 Pkg%pc6 Pkg%pc7 Pkg%pc8 Pkg%pc9 Pk%pc10 PkgWatt CorWatt GFXWatt
     111    4.82    2295    2300       0   10.17    2.63    1.03   81.35      58      58   18.73   49.94    0.00    0.00    0.00    0.00    0.00    4.54    0.86    0.66

EDIT 3: turbostat when completely idle and X turned off

With 3.16.0-36:
Avg_MHz   %Busy Bzy_MHz TSC_MHz     SMI  CPU%c1  CPU%c3  CPU%c6  CPU%c7 CoreTmp  PkgTmp Pkg%pc2 Pkg%pc3 Pkg%pc6 Pkg%pc7 Pkg%pc8 Pkg%pc9 Pk%pc10 PkgWatt CorWatt GFXWatt 
       3    0.30    1133    2300       0    0.53    0.03    0.00   99.14      40      40   18.66    0.28    0.90   78.52    0.00    0.00    0.00    0.97    0.01    0.00

With 3.19.0-15:
 Avg_MHz   %Busy Bzy_MHz TSC_MHz     SMI  CPU%c1  CPU%c3  CPU%c6  CPU%c7 CoreTmp  PkgTmp Pkg%pc2 Pkg%pc3 Pkg%pc6 Pkg%pc7 Pkg%pc8 Pkg%pc9 Pk%pc10 PkgWatt CorWatt GFXWatt
      13    0.64    1970    2300       0    0.89    0.12    0.01   98.35      46      46   18.25   78.78    0.00    0.00    0.00    0.00    0.00    2.28    0.12    0.00

Answer 1

This is a kernel bug reported here: https://bugzilla.kernel.org/show_bug.cgi?id=92111 (many thanks @DougSmythies)

Workaround: add acpi_osi= to the kernel cmdline in /etc/default/grub e.g.:

GRUB_CMDLINE_LINUX="hid_apple.iso_layout=0 elevator=cfq acpi_osi="

run sudo update-grub afterwards and reboot.

This will most likely disable thunderbolt.

Answer 2

In my case, the issue 92111 caused the power usage increase.