Re:Lenovo: researchers find 'massive security risk'
by nitrogen on Wednesday May 06, 2015 @11:06PM
(#9503083)
It can be a combination of factors:
- The CPU fan might be controlled via ACPI.
- The operating system is supposed to run ACPI code provided by the BIOS.
- A BIOS can specify different sets of ACPI code for different operating systems, so Linux might get different code from Windows.
- The ACPI code provided by the BIOS for Linux might be broken, or lacking fan control.
- The hardware vendor may have decided not to provide APCI controls for anything, relying instead on proprietary interfaces.
Section 1.9 of https://www.kernel.org/doc/ols/2005/ols2005v1-pages-59-76.pd... looks like it might be related.
Re:Lenovo: researchers find 'massive security risk'
by ori_b on Wednesday May 06, 2015 @05:13PM
(#9501847)
I think you have it backwards: The CPU fan spins. Until the OS (or the AML bytecode that the OS interprets as a part of ACPI) tells it "the CPU is cool right now, you can slow down and save power".
Re:Lenovo: researchers find 'massive security risk'
by throwawayaway on Wednesday May 06, 2015 @06:10PM
(#9502109)
> On a Thinkpad T500, you do need Lenovos special power management tools. Otherwise, the cpu fan will never spin up and your processor will overheat.
I am replying to this guy. Never spin up? Overheat? He's completely wrong.
I know full well how it works, I don't have it backwards.
Re:Lenovo: researchers find 'massive security risk'
by tsomctl on Wednesday May 06, 2015 @08:12PM
(#9502572)
I'm pretty sure you're trolling, but I'll feed you. I wasn't fully clear. Really what I meant is that the fan always spins at a slow speed. When the processor heats up, the fan doesn't speed up, and eventually the cpu shuts down to protect itself. And I've spent 12 hours a day in front of this computer for the past 5 years. I know how it works.
i'm having a hard time imagining a computer booting, without a cpu fan. OS: I'm starting up - so do all these things! as fast as possible!