CPU coil whine on T400s
Like many others (perhaps everybody?) my T400s produces this annoying noise which I learned from other users is coil whine from the CPU. It appears that some bios/windows users have successfully solved the problem, but the examples I have found are with other machines than the T400s.
The issues has been touched here before, but I still miss a solution: https://trisquel.info/en/forum/whats-deal-corebootlibreboot-x220230-looking-more-powerful-freedom-laptop
My L470 has coil whine. The solution is to use it in an environment with ambient background noise. Start a fan or turn on a radio. That'll make the whine fade and go away from perception.
I solved this problem on my T400s by opening the microphone settings window. I discovered this trick after reading tips from another forum, and it surprisingly works.
Does the noise only concern libreboot t400 computers?
I have several t400 computers. I have not installed
libreboot on them and none of them is noisy.
My guess is that it mainly affects the "s" models, and not the standard T400. If you don't hear any noise, then you should have nothing to worry about.
I missed it is about the t400s.
This also happens with Librebooted Thinkpad X60. The WAS a fix for it. The fix was basically just installing powertop. There was a whole section of the Libreboot website about it.
I say there WAS a fix because it no longer works. It sucks but in the best and latest version of Trisquel that fix actually makes things worse. You can install powertop like the guide says, but the instant you run it the backlight shuts off and I had to shine a really powerful flashlight at my screen to read anything. Only rebooting gets the backlight to turn on again.
Now I just kind of have to live with a constant EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEe noise.