On 10/28/2014 9:20 AM, Rony Ross wrote:
> I'm working on DELL E7440 platform (Haswell based) with dual OS: Windows 8.1 and Ubuntu 14.04.1 (based on 3.13).
> When I use Win 8.1, using BLA I get ~90% PC7 when idle. However, when I use the Ubuntu, using powertop I get only as high as PC3.
> Since it's the same platform, it seems to rule out a HW issue. Any idea what can be the problem? Is Haswell fully supported by powertop?
>

likely some device is not going to a low power state, which then blocks PC7.
Powertop should be able to tell you which device that is