[ltp] New PowerTOP utility for Linux 2.6.21+ from Intel

Henrique de Moraes Holschuh linux-thinkpad@linux-thinkpad.org
Mon, 14 May 2007 23:52:11 -0300


On Sun, 13 May 2007, Chris Hanson wrote:
> output.  hdapsd and the hdaps module, however, are both significant,

That can't be avoided.  hdaps needs to pool the EC at somewhat high
frequencies to be effective (say, 50Hz or so), and that also disturbs the
EC, yes, it is nowhere near cheap in power.

Apple did it better, and placed the shock-detection algorithm inside the EC
and delivers an interrupt if things are bad (OTOH, who knows how good is
that algorithm?), so you don't need to pool the accelerometer firmware to
find out what is happening by yourself.

We *can* make it waste less power moving it entirely to kernel space, but it
will be a marginal gain at best (I doubt one can even measure it).

> problems are: USB at #1 (23%), fglrx at #2 (14%), and ipw3945 at #5

Always remove uhci-hcd unless you *really* need usb 1.1.  ehci-hcd is less
of a power hog at runtime (but do check if you should not be removing it on
sleep-to-ram).

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh