[ltp] Fan-questions again...

[Henrique de Moraes Holschuh]

On Wed, 10 Jan 2007, Benjamin Buch wrote:
> Got my R52 1846-AQG since christmas, running ubuntu edgy.
> I think I love the tp, only thing that annoys me is the fan noise (as I
> read on thinkwiki I'm not the only one...)

Indeed.
http://thinkwiki.org/wiki/Embedded_Controller_Firmware#Bug:_Fan_control_loop_pulses_the_fan_in_an_annoying_pattern

All T43, R52 users that are not either hacking their firmware or using
something like tp_fancontrol are being subject this ridiculous bug.

> -why does the fan start at rather cool temperatures? 
> CPU ~43° (I'm using gnome sensors applet to read it). 

Get the latest ibm-acpi patches, and read the temps from
/proc/acpi/ibm/thermal.  There are 12 of them, and CPU ain't the one that
causes trouble with the fan.

> -what exactly does the MiniPCI-contoller control? With the fan off, this
> temperature rises very slowly to ~55°, and when the fan is turned on
> again it decreases significantly slower than all the other temperatures.

See http://thinkwiki.org/wiki/Thermal_Sensors

> -why are there different fan speeds within the same speed level?

EC bug and the need to work around design limitations on the el-cheapo fan
tachometers used in cooling fans.

> -is the auto-mode in ibm-acpi 0.13 that comes with kernel 2.6.20 the
> same auto-mode programmed by Yury Polyanskiy? (Where you can set min and
> max temperature thresholds)

It is whatever your EC firmware calls "auto mode".  Which is noisy as all
heck due to a bug, unless you hacked your EC firmware.

> -first thing I did was a firmware-upgrade. My impression is that since
> then the tp is more noisy than before. Would it be a good idea to
> "downgrade" firmware? (I have my doubts...)

No.  And it won't help, anyway.

-- 
  "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