[coreboot] Investigating the high pitched noise on the x60 tablet

[Charles Devereaux]

Hello

Now that I have a working coreboot (sadly without the irda and wacom part -
cf next message), I would like to investigate the whining noise issue.

I have a spare motherboard that I'm setting up for studying this noise
issue by pinpointing from which component it comes from - BTW how would it
be possible to have an autopower on option ? I mean, as soon as the AC
adapter is connecter, start booting - because I don't have a spare keyboard
for this spare motherboard :-)

Some remarks on a X60t using a SSD ie quite silent :
 - I have tried physically removing the modem - this introduces a similar
(but less intense) noise using the default bios
 - with the x60t on an ultrabase and coreboot, the same noise is heard
until say 30 minutes, then it become silent - I suppose because of the fan
turning on due to the high temperature or automatic power saving features
(acpi -t report 52 C and 55 C while the CPU load is almost 0)
 - What's more interesting is then, on this silent X60t, running rmmod
uhci_hcd changes nothing but doing insmod uhci_hcd after that reintroduces
the noise !!
 - Even better, as reported on
http://www.kernelconcepts.de/~nils/ibm-x60.html, the UHCI interaction with
ACPI C3 has been a problem in the past :
>"Since 2.6.24 has been released I tried it with some interesting results...
>
>The new power saving features like cpuidle and AC97 suspend did not show
any >results - at first. The reason was that the CPU did almost never enter
C3 when idle >which cause additional 3W (!) of power drain.
>
>The reason is seemingly a change in the USB UHCI - if I remove uhci_hcd
the >CPU goes to C3 again. Strangely this was not necessary with 2.6.22 :("

I will try to read the old patches - maybe the current day uhci module is
not playing nice with acpi on the X60 - for example, going into the
adequate power saving mode only when some specific condition happens (like
on the ultrabase), but by default going into a power saving mode that make
this noise.

There are interesting suggestions on
http://www.thinkwiki.org/wiki/Problem_with_high_pitch_noises

If someone else is interested in making coreboot work perfectly on the
x60tablet, I would be willing to donate a working motherboard (with wifi
module)

Charles
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