Talk:Problem with high pitch noises

Discussion of "Limit ACPI CPU power states"

• Stefan Baums: I raised this issue on the linux-kernel mailing list, and from there it was forwarded to the acpi-devel mailing list. See the discussion here and here. Results: The idle=halt kernel parameter disables ACPI C-state switching entirely (i.e., locks the processor in C1). It is preferable to pass to the ACPI processor component the option max_cstate=2, which only disables the problematic states C3 and C4. The only way to accomplish this that worked for me was to compile the ACPI processor component permanently into the kernel (CONFIG_ACPI_PROCESSOR=y) and then enable it by adding the parameter processor.max_cstate=2 to the boot command line (and of course removing idle=halt). Now the computer switches back and forth between C1 and C2, but avoids the noise-inducing C3 and C4, and frequency scaling works regardless. [Update: I now use the default Ubuntu kernel, with processor as a module, and disabled C3 and C4 by modifying /etc/init.d/acpid as explained on the article page.] (X41)
• Simon Eggert: The processor.max_cstate=3 option worked for me on my T43p thanks.
• Adding options processor max_cstate=2 in /etc/modprobe.conf (or /etc/modprobe.conf.local on my SuSE 9.3 installation) prevents the CPU permanently from entering into C3 and higher states. (X40, R52)
• Thinker: On one T43, this worked even with processor.max_cstate=3. That is, C3 was silent and only C4 produced whining (at both HZ=100 and HZ=250).
• Thinker: These options affect power consumption when the CPU is idle. Here are the figures on one ThinkPad T43:
  • processor.max_cstate=4: 15160mW (default, noisy)
  • processor.max_cstate=3: 15770mW (660mW higher, silent)
  • processor.max_cstate=2: 16100mW (2940mW higher, silent)

• gsmenden: On a debian system, no modprobe.conf, can use modutils to add max_cstate line. On my t43p the noise only occcurs when on battery power after suspend / resume cycle. It is definitely is still present when hard disk is spun down. Nevertheless there may be multiple sources of this (quite annoying) sound.

• gsmenden: Update - if you don't want to use modutils, can manually load it on bootup by adding "processor max_cstate=3" in /etc/modules on a debian system. Noise still present upon resume though on my t43p though  :(

• Nephiel: My Z60m also had the "screeching when on battery" problem with Ubuntu 5.10. Editing /etc/init.d/acpid as described worked. It needed C2: C3 was quieter but still noticeable.

• Michael Kiausch: On my X41 the noise disappears on unloading uhci-hcd module (no matter which c-state), unfortunately this is not an option as this disables usb. edit: only works if HZ=100

• Just tested M. Kiausch's suggestion on a T43. The high-pitch noise is gone (HZ=100, cstate=4), but there is a low-pitch noise with about the same "beat". It is much less audible though, and I really had to keep an ear close to the exhaust to hear it. But the noise is still there.

• Michael Kiausch: You're right, same low-pitch-noise on X41, but it is really hard to hear. Does anyone know in which way the usb-uhci is related to the c-states?

• Slurm The high-pitch noise occurs on my x41 only if i'm on battery and my mouse(usb, optical) is plugged in.

• Martin Aumueller: Upgrading the BIOS on my X60s from 1.04 to 1.06 solved the noise problem for me, however it seems to draw about 500 mW more power with the newer BIOS.

• Piccobello: on an X31, I noticed a very weak sound that seems to be turned on whenever I switch to the performance governor, and is only turned off if I switch to powersave, regardless of wether the battery is used.

Harddisk related noise

on my T43p the noise definitely comes from the harddisk and can be heard both in Windows and Linux. Only at boot time, before the harddisk spins up, or when I manually spin down the harddisk with

# hdparm -y /dev/sda

the system is silent.

Hi, I don't have an IBM but Dell Latitude D410 laptop. My problem is that not only the high pitch noise is produced but the processor itself comes very busy when speedstep-centrino module is loaded. On karamba monitor (not very reliable but I can feel the difference) I get 50-100% processor occupation. Right now I'm recompiling my 2.6.14 kernel to 100Hz timer freq. (was 250) and we'll see what happens.

If you have any suggestions don't hestite since I practically can't use speedsteping because battery discharges rapidly

Cheers Wojtek

Noise from Wlan

Hi, I have a high frequency noise from my wifi modul: It occurs only with linux, only in battery mode. Disabling wifi via hardware switch disables the noise!
Any Ideas?
Florian

EDIT: Giving the cpus something to calc disables the noise, too!
EDIT2: "Turn off CPU power saving in in BIOS" seems (!!) to solve the problem! But where is the connection to the wlan?

Noise from Fan

http://forum.thinkpads.com/viewtopic.php?p=171683

Noise from Microphone on the T60

I found out that the "pitching" noise while workin on battery could be solved else as setting "cstate" to "2" and loosing battery time.

The real problem about the pitching noise on my T60 is the misplacement of the microphone, which seems to be vulnerable to the frequencies the processor is generating on cstates above "2"!

Now the fix which has worked for me is:

Setting the module option "position_fix=2"!

Thanks to the existing Thinkwiki article about the soundcard: http://www.thinkwiki.org/wiki/AD1981HD

Debian: open up the /etc/modprobe.d/alsa-base file and go to the line where "snd-hda-intel" is loaded. After this line insert "options snd-hda-intel position_fix=2".

Reload your alsa config and enjoy the silence!!!

Noise from LCD

Dimming lcd (via fn-home/end or acpi) results in a noise. Only resolution is to keep lcd at full brightness or turned off. More info about dimming used in laptops