[ltp] [solved] x61s hot palm rest

[Nils Faerber]

Richard Neill schrieb:
> Christian Fromme wrote:
>> On 05.10. 21:32, Damien Challet wrote:
>>> Pulseaudio was the culprit:
>>> apt-get remove puleaudio*
>>> and now this laptop begins to be usable.
>>> Thanks the help of everybody.
>> Thanks for the update
> 
> Have you managed to find out *why* PA was doing this? I suspect the devs
> might appreciate a bug report.
> 
> I'm no fan of PA for various other reasons, but I'd never have suspected
> it of acting as an auxilliary heater.

Depending on the version (I am not sure which one might be better) PA
constantly sends a PCM stream to the soundcard to avoid clicking when
starting and stopping the stream.
But this causes the AC97 to never sleep but even worse the CPU to spend
endless cycles in DMA transfers to the soundcard which causes the CPU
almost never to reach C3. This causes additional power drain and thus heat.
But it amazes me that in the X61s the palmrest gets hot when the CPU is
active!? The CPU should be located somewhere else not under the palmrest
- strange.

> Given that hacking is quite fun (eg turning the HDAPS system into a
> joystick: http://www.thinkwiki.org/wiki/HDAPS#Tilt_monitoring ),
> how about writing a little applet to enable the "wrist-heater" for cold
> days (rather like heated handlebars on a motorbike)  ;-)

:)

> Richard
Cheers
  nils faerber

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