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

[Henrique de Moraes Holschuh]

On Tue, 15 May 2007, Chris Hanson wrote:
> Henrique de Moraes Holschuh wrote:
> > 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.
> 
> Hmmm... but PowerTOP seems to indicate that the kernel module and the
> userspace daemon are each independently polling at 50Hz, which could be
> improved.

Yes.  The input device interface would fix this.

> >> 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
> 
> I didn't know that it was possible to use USB 1.1 devices with ehci-hcd.
>    Can I just blacklist uhci-hcd in module-utils?

It is not. That's why I said "Unless you really need usb 1.1".  Most of my
devices are USB 2.0, so I just ditch uhci-hcd when I only need usb 2.0.

> > (but do check if you should not be removing it on sleep-to-ram).
> 
> How do I check that?  By trying it and looking for lossage?  I thought
> that unloading the USB drivers was standard practice for any kind of
> suspend.

See thinkwiki.org.  And while we *do* remove the *-hcd drivers before S3
most of the time, that really should not be needed.  Kernel bugs and missing
features, what a nuisance ;-)

> (an X31).  Maybe things are better now.

The T4x machines work wonderfully.  All *60 machines are on risk of becoming
crap because of all the damage Lenovo is doing to their BIOS while trying to
make them work with Windows Vista.

> By the way, it turns out that the high USB interrupts go away if the
> wireless kill switch is changed to disable wireless.  I'm guessing the
> interrupts have something to do with bluetooth.

Yes, the bluetooth module is a USB1.1 device.

-- 
  "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