[ltp] X61 power consumption

[Leszek Koltunski]

> |08:03.4 FireWire (IEEE 1394): O2 Micro, Inc. Firewire (IEEE 1394) (rev 02) (prog-if 10 [OHCI])
> |	Capabilities: [60] Power Management version 2
> |		Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA PME(D0+,D1+,D2+,D3hot+,D3cold-)
> |		Status: D0 PME-Enable- DSel=0 DScale=0 PME+
>
> It tells you that the states D1 and D2 are supported (by the "+" behind
> the state identifiers), D0 and D3 are always supported.
>
> To select the state, read the word at offset 4 in the power management
> structure, in this case 0x60 (from lspci output) plus 4, and write the
> D-State into the lowest two bits. For example:
>
> | hermes2:~# setpci -s 8:3.4 0x64.W
> | 8000
> | hermes2:~# setpci -s 8:3.4 0x64.W=0x8003
> Enters D3 mode. In that mode, the device does not have to behave anyhow
> useful on the bus until you reset the mode to D0! That even applies to
> config space except for the power management control register, so lspci
> -H1 might show you an invalid PCI ID of that device. So, unload the
> module before trying that, or you risk hard crashes. And set the mode
> back to D0 before trying to load the module again.

Thanks! Although I just did exactly the above and I cannot see any 
measurable difference... Obviously I am missing something or there's 
something grossly wrong with Linux power management.

Now I see I forgot to unload the e1000e module in my original test. I just 
did that and I saw 9.9W 'lowest momentarily draw'. Also the graphics chip; 
is there a way to put the 965GM into power-saving mode? Oh, and I probably 
should have disabled the VGA output! How do I do that?

Anyone has a X61 with similar specs and can go lower than 9.9? Basically: 
what is the lowest number you can see in powertop - all software tricks 
are fair game as long as you still can run and see powertop, of course :)