Problem with high pitch noises
Information on strange high pitch, low volume noises emitted by ThinkPads.
Problem description
Even though ThinkPads are known as very silent notebooks, they tend to emit different, mostly high pitch noises in certain circumstances. The noises are of low volume and hence not realized by everyone or at least tolerated by most people. However, there are those with "bat like ears" that hear them and might be annoyed by that.
Affected Models
Noises have been experienced in the following situations:
| situation | noise description | affected models |
|---|---|---|
|
ThinkPad suspended to RAM |
constant high pitch noise |
|
|
ThinkPad connected to power and switched off, with battery fully charged |
constant high pitch noise |
|
|
moving windows or just the mouse in xorg |
strange noise like a rapid series of very short high pitch noises adding to a constant kind of whistling (only as long as the movement goes) |
|
|
Thinkpad connected to power or working on battery, also when suspended to RAM |
High pitch noise also when HD is powered down. |
|
|
Thinkpad connected to power battery charged less than 60% |
High pitch noise till battery is charged more than 60%. |
|
|
Constantly, if AC connected |
High pitched, low volume constant noise. |
|
Affected Operating Systems
- Linux, all flavours
Status
Similar phenomena was experienced with models from the T2x aera, like i.e. on the T23. On these models the problem was related to the graphics circuitry and occured especially or only while making use of DirectDraw funktions. IBM was able to fix it through a BIOS upgrade.
It is likely that the noises discovered on recent models are related to the graphics chip as well.
Solutions
From Martin Steigerwald: I made the observation that I get at least less high pitch noises on my ThinkPad T23 when I do not use the two ACPI modules "processor" and "thermal" (depends on the first one). I have no clue, why. Anyone with similar experiences?
Niko Ehrenfeuchter: I'm experiencing the same here on my X24. Removing the "processor" module also stops the pitch noise, which does ONLY occur when setting the CPU to maximum speed (using cpufreq). On low speed it's completely silent, even having loaded the processor module.
Rolf Adelsberger: I can confirm this: the high pitch noise is only remarkable (at least with my ears ;-) ) if the processor speed is set to maximum frequency.
Andreas Karnahl: i've read in several forums it has something to do with the "idle"-state (or "C3") of the processor. there is a frequency called "timer interrupt" (or something like that). since kernel 2.6x it is set to 1000 Hz by default (compared to 100 Hz in Kernel 2.4x). the exact reason i don't no. but it is save to change this frequency to 100 Hz in kernel 2.6x (by the way, windows up to XP uses 100 Hz by default).
just do the following:
in [path to kernel-sources]/include/asm-i386/param.h:
#define HZ 1000
change the value of HZ to 100:
#define HZ 100
... and compile the kernel ...
after i changed it on my ThinkPad A30 (under SuSE 9.2 and 9.3) and recompiling the kernel the high pitch noise is gone away.
Joern Heissler: I made another experience. I played around with linuxant conexant modem drivers. After loading them I got some noise on my t42p
Naheed Vora: My T41 (2373-268) started to give high pitch noise ocassionally, when I upgraded to 2.6.11 kernel. I tried to unload lot of modules but finally figured out that disabling bay stops the noice.
If you have ibm_acpi module, do (Need a cleaner solution):
echo eject >/proc/acpi/ibm/bay
