On Wed, May 20, 2015 at 08:56:57PM -0600, Shaun Reiger wrote:
> Hello I'm trying to find out if the power consumption relating to the
> intel_powerclamp driver ("Package Level C-state Idle Injection for
> Intel CPUs") was ever fixed. I'm current running 5.7 stable and I find
> my cpu is still consuming 6W of power in any state. It was mentioned
> in the emails from last year that a Linux driver fixed this issue. Any
> updates on this issue would be great. I have attached my dmesg for
> review.
>
> Thanks
There was some work in progress for C-state support by guenther@ but
I'm not sure what the current status is. I got about one additional
hour of battery life out of it when I tested it once. With plain
-current I get about 2h of runtime out of the battery.
Getting to the levels of Linux (additional 4 hours in my case) probably
requires invasive changes to the process scheduler (prevent it from
scheduling processes on certain cores to avoid waking them) and/or the
inteldrm(4) driver (to put the GPU into power-save mode).
It seems the x201 has a CPU generation which requires a ton of special
support code in drivers for good power saving, while subsequent
generations of laptops (x220 and later) use CPUs which don't really
require that much of it. Overall I'm not sure it's really worth pouring
a lot of development resources into optimizing for the x201 generation.
Other laptops already run much longer.
