I could be confusing the name. I believe pm-powersave is a subset of pm-utils. I typically install/use laptop-mode (installed via apt-get). On this Mint install, I followed suit, but realized shortly later that it wasn't working. Dug deeper and discovered that pm-powersave was installed and it contains a subset of laptop-mode and they cannot co-exist together or neither will work. I can invoke laptop mode by either running pm-powersave true or setting a non-zero integer (such as 5) in the laptop_mode file under /sys/...
It still seems like you're confusing the kernel usage of the term "laptop mode" with the software package Laptop Mode Tools.
To the best of my knowledge, pm-utils does not "contain a subset of laptop mode", but rather uses the *kernel*'s laptop mode setting (in addition to other things) in an attempt to improve power usage.
For more information, you might want to check out LMT's home page
Personally I use LMT. I have pm-utils installed, but I don't have it set up to do anything. LMT handles all of my power saving config just fine. I can help you configure your box in a similar manner and it will work, but if you don't want to use LMT I'm afraid that I'll be somewhat more limited in terms of the advice that I can offer.
It's a parameter in the configuration. The default is false but I have modified the configuration to true to enable.
Are you referring to /sys/module/pcie_aspm/parameters/policy ? Because that only takes effect if ASPM is enabled -- and on most ThinkPads it's disabled by default due to BIOS quirks (hence the need for the command line options.) Again, I recommend you check what the ASPM support check shows in your kernel log and go from there.
A few friends have told me the same, so was always on the fence on the subject. I started reading through a bit more on the governance models, and they do recommend on-demand or conservative over powersave as the typical net result is better power savings.
I'm going to finish doing some more research and then try monitoring consumption under various situations.
When last I looked at the implementation, the only difference between the conservative and on-demand governors was how aggressive they were about up-clocking under load. Conservative used a much more, well, conservative scaling approach whereas on-demand almost immediately ramps to the top frequency. In general, this means that on-demand gets the work done faster which (on modern chips) means a faster return to sleep states. This is what you want.
A question about FBC and LVDS.... do these need to be enabled, and how? I was starting to dig up some information on these and found information suggesting they are enabled by default in the newer kernels.
Oh god, the i915 options... well it depends on the kernel version. It seems like the defaults for that are *always* changing thanks to the insane number of hardware bugs that the DRM devs discover.
As of 3.2.6 (what my current local kernel is based on):
root@kestrel:/etc/pm# modinfo i915
license: GPL and additional rights
description: Intel Graphics
author: Tungsten Graphics, Inc.
license: GPL and additional rights
vermagic: 3.2.6-grsec SMP preempt mod_unload modversions KERNEXEC_BTS UDEREF REFCOUNT GRSEC
parm: modeset:Use kernel modesetting [KMS] (0=DRM_I915_KMS from .config, 1=on, -1=force vga console preference [default]) (int)
parm: panel_ignore_lid:Override lid status (0=autodetect [default], 1=lid open, -1=lid closed) (int)
parm: powersave:Enable powersavings, fbc, downclocking, etc. (default: true) (int)
parm: semaphores:Use semaphores for inter-ring sync (default: -1 (use per-chip defaults)) (int)
parm: i915_enable_rc6:Enable power-saving render C-state 6 (default: -1 (use per-chip default) (int)
parm: i915_enable_fbc:Enable frame buffer compression for power savings (default: -1 (use per-chip default)) (int)
parm: lvds_downclock:Use panel (LVDS/eDP) downclocking for power savings (default: false) (int)
parm: lvds_use_ssc:Use Spread Spectrum Clock with panels [LVDS/eDP] (default: auto from VBT) (int)
parm: vbt_sdvo_panel_type:Override selection of SDVO panel mode in the VBT (default: auto) (int)
parm: reset:Attempt GPU resets (default: true) (bool)
parm: enable_hangcheck:Periodically check GPU activity for detecting hangs. WARNING: Disabling this can cause system wide hangs. (default: true) (bool)
I'd recommend you check your kernel though, since your defaults may very well be different.
Need help with Linux or FreeBSD? Catch me on IRC: I'm ThinkRob on FreeNode and EFnet.
Current laptop: Lenovo ThinkPad T420 (running Debian Wheezy) - kestrel [pending retirement]
Current workstation: IBM Intellistation 9228 (running FreeBSD 9.1) - blackbird