ThinkWiki - User contributions [en]

Problem with high pitch noises

2006-10-18T06:01:25Z

Ccshan: /* Limit ACPI CPU power states */

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:
{| border="1" cellspacing="0" cellpadding="2"
|-
! style="vertical-align:top;background-color:#DDDDDD;" | situation
! style="vertical-align:top;background-color:#DDDDDD;" | noise description
! style="vertical-align:top;background-color:#DDDDDD;" | affected models
|-
| style="vertical-align:top;" |
Plugged into AC / running at high CPU frequency
| style="vertical-align:top;" |
soft crackling, buzzing noise
| style="vertical-align:top;" |
*{{T41}}
**2379-DJU
|-
| style="vertical-align:top;" |
ThinkPad suspended to RAM
| style="vertical-align:top;" |
constant high pitch noise
| style="vertical-align:top;" |
*{{T42p}}
|-
| style="vertical-align:top;" |
ThinkPad connected to power and switched off, with battery fully charged
| style="vertical-align:top;" |
constant high pitch noise
| style="vertical-align:top;" |
*{{T41p}}
**2373-GHG
|-
| style="vertical-align:top;" |
moving windows or just the mouse in xorg
| style="vertical-align:top;" |
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)
| style="vertical-align:top;" |
*{{T41p}}
**2373-GHG
|-
| style="vertical-align:top;" |
Thinkpad connected to power or working on battery, also when suspended to RAM
| style="vertical-align:top;" |
High pitch noise also when HD is powered down.
| style="vertical-align:top;" |
*{{T23}}
**2647-DG4
*{{X24}}
**2662-MWG
|-
| style="vertical-align:top;" |
Thinkpad connected to power battery charged less than 60%
| style="vertical-align:top;" |
High pitch noise till battery is charged more than 60%.
| style="vertical-align:top;" |
*{{T41p}}
**2373-GEG
|-
| style="vertical-align:top;" |
Constantly, if AC connected
| style="vertical-align:top;" |
High pitched, low volume constant noise.
| style="vertical-align:top;" |
*{{T40}}
**2373-88U
|-
| style="vertical-align:top;" |
When the CPU freq jumps up to 1Ghz or above, or when the laptop is in suspend mode
| style="vertical-align:top;" |
Constant high pitched
| style="vertical-align:top;" |
*{{R50}}
**1829-6DM
|-
| style="vertical-align:top;" |
(May come from harddisk.)
| style="vertical-align:top;" |
continuous, intermittent, low volume, high pitched
| style="vertical-align:top;" |
*{{600X}}
|-
| style="vertical-align:top;" |
ACPI puts the processor into the C3 or C4 power saving states (i.e., the system is idle).
| style="vertical-align:top;" |
High-pitched crackling noise.
| style="vertical-align:top;" |
*{{X41}}
*{{T43}}
**2686-DGU
*{{T43p}}
*{{T60}}
**2007-72U
*{{T21}}
*{{T20}}
**2648-46U
|-
| style="vertical-align:top;" |
Cpufreqd (or powernowd etc.) slows down the processor, for exemple at the end of an heavy task.
| style="vertical-align:top;" |
High-pitched crackling noise.
| style="vertical-align:top;" |
*{{T42}}
|-
| style="vertical-align:top;" |
When on battery
| style="vertical-align:top;" |
Almost inaudible screeching sound, or sometimes beeping (when wifi is on)
| style="vertical-align:top;" |
*{{R52}}
**1858-A11
*{{T43}}
**2686-DGU
**1871-4AG
*{{T60}}
**2007-72U
*{{x60}}
*{{x31}}
**2673-CBU

|-
| CPU is used much AND laptop is on AC power AND the TFT panel is enabled.
| Screetching high pitch noise, like a million crickets
|
* {{X41}}

|-
| Network is pluged in and networkload is ~100%.
| low volume highfreq. pitch noise from left speaker or cpu.
|
*{{Z60m}}, {{Z60t}}
*{{T43}}
**2687-DDU
|}

==Affected Operating Systems==
All, though Linux appears especially susceptible.

==Possible sources==

* '''CPU activity:''' On some models the noise is triggered by certain CPU power states or activity patterns (as proven [http://www.wisdom.weizmann.ac.il/~tromer/acoustic here]).
* '''Graphics processor:''' In some models from the T2x era, e.g. the {{T23}}, the problem was related to the graphics circuitry and occured especially or only while making use of DirectDraw functions. IBM was able to fix it through a BIOS upgrade.
* '''Hard disk:''' On some ThinkPads the processor and hard disk are adjacent and produce similar noise. For example, in the {{X41}} the sound generated by the hard disk is likely to be loudest at the vent.
* '''Gigabit Ethernet processor:''' In some models (e.g., {{T43}}) high ethernet activity causes a high pitch noise.

==Status==

The problem is highly specific to operating system, model and even individual machines. There is no universal solution, but on most machines one of the following will reduce or eliminate the noise (possibly at some cost in power consumption).

==Solutions for CPU-triggered noise==

===Limit ACPI CPU power states===

There are four ACPI CPU power states, called C1 through C4. Often only the extreme power saving modes C4 or C3 produce the noise, so the noise can be stopped by insructing the Linux ACPI code to use only lower modes.

To forbid the ACPI driver from using C4 (this fixed the problem with on some ThinkPad {{T43}}, {{T43p}} and {{T41}}):
* If the ACPI processor component is compiled as built-in (<tt>CONFIG_ACPI_PROCESSOR=y</tt>):
**Pass the {{bootparm|max_cstate|3}} kernel argument.
* If the ACPI processor component is loaded as a module (<tt>CONFIG_ACPI_PROCESSOR=m</tt> and <tt>processor</tt> shows in the output of {{cmdroot|lsmod}}), do either of:
** Pass the {{bootparm|processor.max_cstate|3}} kernel argument (this does not work in Ubuntu 5.10 with default kernel).
** Add <code>options processor max_cstate=3</code> to {{path|/etc/modprobe.conf}} (or {{path|/etc/modprobe.conf.local}}, or {{path|/etc/modprobe.d/...}}, depending on your system) (this does not work in Ubuntu 5.10 with default kernel).
** {{cmdroot|echo 3 > /sys/module/processor/parameters/max_cstate}} (this can be changed in runtime for experimentation). (If may need to be set again upon resume from suspend, e.g., in the wakeup script.)
** (On Ubuntu 5.10, the default kernel uses <code>processor</code> as a module. Unfortunately, the script loading it, {{path|/etc/init.d/acpid}}, ignores the <code>options processor max_cstate=3</code> setting in {{path|/etc/modprobe.d/<my file>}}. As a solution for this specific problem, add the line <code>echo 2 > /sys/module/processor/parameters/max_cstate</code> directly to {{path|/etc/init.d/acpid}}, at the end of the function <code>load_modules()</code>, immediately after the line <code>echo "$PRINTK" > /proc/sys/kernel/printk</code>.)

To also forbid the C3 state, replace "<tt>3</tt>" with "<tt>2</tt>" above (this fixed the problem on some ThinkPad {{X40}}, {{X41}}, {{X60}}, and {{R52}}, as well as on {{T20}} where C4 is not supported at all):

Note that these options affect power consumption when the CPU is idle. For example, here is the [[How to measure power consumption|measured power consumption]] on a ThinkPad {{T43}}:
* {{bootparm|processor.max_cstate|4}}: 15160mW (default, noisy)
* {{bootparm|processor.max_cstate|3}}: 15770mW (660mW higher, silent)
* {{bootparm|processor.max_cstate|2}}: 16100mW (2940mW higher, silent)

See the [http://thinkwiki.org/wiki?title=Talk:Problem_with_high_pitch_noises discussion page] for further information and success reports.

*Jakob Schou Pedersen: Editing the file {{path|/etc/init.d/acpid}} as described above (the last solution) worked on my T43 :-)

===Turn off CPU power saving in in BIOS===

Go into the BIOS and turn off the power saving processor feature that puts it into idle mode. (This worked on a ThinkPad {{T43}}, {{T21}} and {{X60s}}.)

===Disable ACPI CPU power states===

Completely disable CPU ACPI power states. Discussion:

*From Martin Steigerwald: I made the observation that I get at least less high pitch noises on my {{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?
:Omar Yasin: I've got a {{R52}} and when I load the same ACPIO modules the high pitch noises are not as loud but I can still hear them.
*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.

*Stefan Baums: My {{X41}} produced a high-pitched crackle from the processor vent on the left. Changing HZ did nothing, and the 'processor' module could not easily be removed from the system (Ubuntu 5.04). What solved the problem for me was adding {{bootparm|idle|halt}} to the boot command line. Unfortunately, this solution only lasts until the first hibernation or suspend - when the computer ({{X41}}) resumes, the high-pitched crackle is back.

* The {{bootparm|idle|halt}} solution combined with setting <code>#define HZ 100</code> in the kernel fixes the problem on a {{T43}}.

* jhatch: {{bootparm|idle|halt}} plus <code>#define HZ 100</code> also worked on my {{T43}}. It still reverts back to noisy after a suspend/resume though. This needs to be fixed...

===Change the timer interrupt frequency===

Change the "HZ" kernel constants to alter the frequency of timer interrupts. Discussion:

{{NOTE|The timer interrupt frequency (HZ) in current Linux kernels is directly tied to the kernel task scheduler. Lower frequencies provide larger time-slices and thus also higher latencies (which may kill latency-sensitive applications like audio processing). 100Hz ended up as the recommended "server" setting (because it increases disk/CPU throughput in a latency-insensitive environment). Higher frequencies are better for latency-sensitive applications, and improve desktop responsivity at the cost of less processor throughput. 1000Hz ended up as the recommended "desktop" setting.}}

*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 so mething 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 know, but it is safe 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|[path to kernel-sources]/include/asm-i386/param.h}} find the line
:: <code>#define HZ 1000</code>
: and change the value of HZ to 100:
:: <code>#define HZ 100</code>
:Then recompile 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.

* Omar Yasin: Worked on my {{R52}}, thanks.

* [[User:Thinker|Thinker]]: In modern kernels this constant is in the kernel configuration {{kernelconf|CONFIG_HZ|Processor type and features||Timer Frequency|||||}}.

===Prevent idling===

Indirectly avoid power saving states by making sure the CPU is rarely idle:

* Paul RIVIER: Here is a really simple workaround. C3 / C4 states are mainly called when the cpu freq is higher than required, for example if your cpufreqd is lazy to slow down the frequency but quick to raise it. That is why I use powernowd with the builtin "passive" mode, which is lazy for raising frequency, but quick to go back to the lowest. Now I don't hear them as often as before, as I avoid C3/C4 states at high frequency.

* The problem also occurs on my {{X41}} with 2.6.11. Setting up [[How to make use of Dynamic Frequency Scaling|frequency scaling]] with the <code>ondemand</code> governor makes things a lot better, as the processor does not stay with the maximum frequency when in idle mode. It can be still heard sometimes, though.

* On a {{T43}} the noise was gone after dropping cpufreqd and switching to the ondemand governor - maybe because of the high sampling rate? (used the default: 10ms)

===Change the processor voltage===

Reducing the processor voltage (when possible) may decrease or eliminate the noise. On one ThinkPad {{T43}}, [[Pentium M undervolting and underclocking|undervolting the Pentium M processor]] eliminated the high-pitched noise. Compared to the other solutions this has the benefit of lower power consumption, both due to the undervolting itself and because there is no need to forbid high APCI CPU power saving modes.

==Other solutions==

===Disable UltraBay===
*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 noise. If you have [[ibm-acpi]], do (need a cleaner solution): {{cmduser|echo eject >/proc/acpi/ibm/bay}} .

===Disable IrDA===
*Mike Perry: I was able to cure an intermittent high-pitched whine on both my {{X24}} and {{X40}} by disabling the Infrared port.

===Disable the Linuxant Modem Driver===
*Joern Heissler: I made another experience. I played around with linuxant conexant [[Modem Devices|modem]] drivers. After loading them I got some noise on my {{T42p}}.

===Media Player paused===
*Eilif Muller: On my {{R52}} the high-pitched noises go away if I load XMMS, play something then pause it.
*Jacob: On my {{T43}} DGU it goes away if I open mplayerc.exe and press play then pause it. This is the high-pitched noise that only shows up when I'm on battery.

''I'd guess that the above tip works as when xmms or similar is running, it is uncompressing compressed audio/video, which is a processor intensive action. Keeping this paused means that the app won't 'let go' of the processor, forcing it to stay up and running, which stops it entering the higher powersave modes.''

===Upgrade BIOS===
On a ThinkPad [[X60s]], [[BIOS_Upgrade|upgrading the BIOS]] to version 1.06 eliminated the high pitch noise when running on battery.

===Disable USB===
On one {{T43}} and one {{X60}}, (partially) disabling USB using {{cmdroot|rmmod uhci_hcd}} significantly reduced the noise.

Problem with high pitch noises

2006-10-18T06:00:33Z

Ccshan: /* Disable USB */

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:
{| border="1" cellspacing="0" cellpadding="2"
|-
! style="vertical-align:top;background-color:#DDDDDD;" | situation
! style="vertical-align:top;background-color:#DDDDDD;" | noise description
! style="vertical-align:top;background-color:#DDDDDD;" | affected models
|-
| style="vertical-align:top;" |
Plugged into AC / running at high CPU frequency
| style="vertical-align:top;" |
soft crackling, buzzing noise
| style="vertical-align:top;" |
*{{T41}}
**2379-DJU
|-
| style="vertical-align:top;" |
ThinkPad suspended to RAM
| style="vertical-align:top;" |
constant high pitch noise
| style="vertical-align:top;" |
*{{T42p}}
|-
| style="vertical-align:top;" |
ThinkPad connected to power and switched off, with battery fully charged
| style="vertical-align:top;" |
constant high pitch noise
| style="vertical-align:top;" |
*{{T41p}}
**2373-GHG
|-
| style="vertical-align:top;" |
moving windows or just the mouse in xorg
| style="vertical-align:top;" |
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)
| style="vertical-align:top;" |
*{{T41p}}
**2373-GHG
|-
| style="vertical-align:top;" |
Thinkpad connected to power or working on battery, also when suspended to RAM
| style="vertical-align:top;" |
High pitch noise also when HD is powered down.
| style="vertical-align:top;" |
*{{T23}}
**2647-DG4
*{{X24}}
**2662-MWG
|-
| style="vertical-align:top;" |
Thinkpad connected to power battery charged less than 60%
| style="vertical-align:top;" |
High pitch noise till battery is charged more than 60%.
| style="vertical-align:top;" |
*{{T41p}}
**2373-GEG
|-
| style="vertical-align:top;" |
Constantly, if AC connected
| style="vertical-align:top;" |
High pitched, low volume constant noise.
| style="vertical-align:top;" |
*{{T40}}
**2373-88U
|-
| style="vertical-align:top;" |
When the CPU freq jumps up to 1Ghz or above, or when the laptop is in suspend mode
| style="vertical-align:top;" |
Constant high pitched
| style="vertical-align:top;" |
*{{R50}}
**1829-6DM
|-
| style="vertical-align:top;" |
(May come from harddisk.)
| style="vertical-align:top;" |
continuous, intermittent, low volume, high pitched
| style="vertical-align:top;" |
*{{600X}}
|-
| style="vertical-align:top;" |
ACPI puts the processor into the C3 or C4 power saving states (i.e., the system is idle).
| style="vertical-align:top;" |
High-pitched crackling noise.
| style="vertical-align:top;" |
*{{X41}}
*{{T43}}
**2686-DGU
*{{T43p}}
*{{T60}}
**2007-72U
*{{T21}}
*{{T20}}
**2648-46U
|-
| style="vertical-align:top;" |
Cpufreqd (or powernowd etc.) slows down the processor, for exemple at the end of an heavy task.
| style="vertical-align:top;" |
High-pitched crackling noise.
| style="vertical-align:top;" |
*{{T42}}
|-
| style="vertical-align:top;" |
When on battery
| style="vertical-align:top;" |
Almost inaudible screeching sound, or sometimes beeping (when wifi is on)
| style="vertical-align:top;" |
*{{R52}}
**1858-A11
*{{T43}}
**2686-DGU
**1871-4AG
*{{T60}}
**2007-72U
*{{x60}}
*{{x31}}
**2673-CBU

|-
| CPU is used much AND laptop is on AC power AND the TFT panel is enabled.
| Screetching high pitch noise, like a million crickets
|
* {{X41}}

|-
| Network is pluged in and networkload is ~100%.
| low volume highfreq. pitch noise from left speaker or cpu.
|
*{{Z60m}}, {{Z60t}}
*{{T43}}
**2687-DDU
|}

==Affected Operating Systems==
All, though Linux appears especially susceptible.

==Possible sources==

* '''CPU activity:''' On some models the noise is triggered by certain CPU power states or activity patterns (as proven [http://www.wisdom.weizmann.ac.il/~tromer/acoustic here]).
* '''Graphics processor:''' In some models from the T2x era, e.g. the {{T23}}, the problem was related to the graphics circuitry and occured especially or only while making use of DirectDraw functions. IBM was able to fix it through a BIOS upgrade.
* '''Hard disk:''' On some ThinkPads the processor and hard disk are adjacent and produce similar noise. For example, in the {{X41}} the sound generated by the hard disk is likely to be loudest at the vent.
* '''Gigabit Ethernet processor:''' In some models (e.g., {{T43}}) high ethernet activity causes a high pitch noise.

==Status==

The problem is highly specific to operating system, model and even individual machines. There is no universal solution, but on most machines one of the following will reduce or eliminate the noise (possibly at some cost in power consumption).

==Solutions for CPU-triggered noise==

===Limit ACPI CPU power states===

There are four ACPI CPU power states, called C1 through C4. Often only the extreme power saving modes C4 or C3 produce the noise, so the noise can be stopped by insructing the Linux ACPI code to use only lower modes.

To forbid the ACPI driver from using C4 (this fixed the problem with on some ThinkPad {{T43}}, {{T43p}} and {{T41}}):
* If the ACPI processor component is compiled as built-in (<tt>CONFIG_ACPI_PROCESSOR=y</tt>):
**Pass the {{bootparm|max_cstate|3}} kernel argument.
* If the ACPI processor component is loaded as a module (<tt>CONFIG_ACPI_PROCESSOR=m</tt> and <tt>processor</tt> shows in the output of {{cmdroot|lsmod}}), do either of:
** Pass the {{bootparm|processor.max_cstate|3}} kernel argument (this does not work in Ubuntu 5.10 with default kernel).
** Add <code>options processor max_cstate=3</code> to {{path|/etc/modprobe.conf}} (or {{path|/etc/modprobe.conf.local}}, or {{path|/etc/modprobe.d/...}}, depending on your system) (this does not work in Ubuntu 5.10 with default kernel).
** {{cmdroot|echo 3 > /sys/module/processor/parameters/max_cstate}} (this can be changed in runtime for experimentation). (If may need to be set again upon resume from suspend, e.g., in the wakeup script.)
** (On Ubuntu 5.10, the default kernel uses <code>processor</code> as a module. Unfortunately, the script loading it, {{path|/etc/init.d/acpid}}, ignores the <code>options processor max_cstate=3</code> setting in {{path|/etc/modprobe.d/<my file>}}. As a solution for this specific problem, add the line <code>echo 2 > /sys/module/processor/parameters/max_cstate</code> directly to {{path|/etc/init.d/acpid}}, at the end of the function <code>load_modules()</code>, immediately after the line <code>echo "$PRINTK" > /proc/sys/kernel/printk</code>.)

To also forbid the C3 state, replace "<tt>3</tt>" with "<tt>2</tt>" above (this fixed the problem on some ThinkPad {{X40}}, {{X41}}, and {{R52}}, as well as on {{T20}} where C4 is not supported at all):

Note that these options affect power consumption when the CPU is idle. For example, here is the [[How to measure power consumption|measured power consumption]] on a ThinkPad {{T43}}:
* {{bootparm|processor.max_cstate|4}}: 15160mW (default, noisy)
* {{bootparm|processor.max_cstate|3}}: 15770mW (660mW higher, silent)
* {{bootparm|processor.max_cstate|2}}: 16100mW (2940mW higher, silent)

See the [http://thinkwiki.org/wiki?title=Talk:Problem_with_high_pitch_noises discussion page] for further information and success reports.

*Jakob Schou Pedersen: Editing the file {{path|/etc/init.d/acpid}} as described above (the last solution) worked on my T43 :-)

===Turn off CPU power saving in in BIOS===

Go into the BIOS and turn off the power saving processor feature that puts it into idle mode. (This worked on a ThinkPad {{T43}}, {{T21}} and {{X60s}}.)

===Disable ACPI CPU power states===

Completely disable CPU ACPI power states. Discussion:

*From Martin Steigerwald: I made the observation that I get at least less high pitch noises on my {{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?
:Omar Yasin: I've got a {{R52}} and when I load the same ACPIO modules the high pitch noises are not as loud but I can still hear them.
*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.

*Stefan Baums: My {{X41}} produced a high-pitched crackle from the processor vent on the left. Changing HZ did nothing, and the 'processor' module could not easily be removed from the system (Ubuntu 5.04). What solved the problem for me was adding {{bootparm|idle|halt}} to the boot command line. Unfortunately, this solution only lasts until the first hibernation or suspend - when the computer ({{X41}}) resumes, the high-pitched crackle is back.

* The {{bootparm|idle|halt}} solution combined with setting <code>#define HZ 100</code> in the kernel fixes the problem on a {{T43}}.

* jhatch: {{bootparm|idle|halt}} plus <code>#define HZ 100</code> also worked on my {{T43}}. It still reverts back to noisy after a suspend/resume though. This needs to be fixed...

===Change the timer interrupt frequency===

Change the "HZ" kernel constants to alter the frequency of timer interrupts. Discussion:

{{NOTE|The timer interrupt frequency (HZ) in current Linux kernels is directly tied to the kernel task scheduler. Lower frequencies provide larger time-slices and thus also higher latencies (which may kill latency-sensitive applications like audio processing). 100Hz ended up as the recommended "server" setting (because it increases disk/CPU throughput in a latency-insensitive environment). Higher frequencies are better for latency-sensitive applications, and improve desktop responsivity at the cost of less processor throughput. 1000Hz ended up as the recommended "desktop" setting.}}

*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 so mething 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 know, but it is safe 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|[path to kernel-sources]/include/asm-i386/param.h}} find the line
:: <code>#define HZ 1000</code>
: and change the value of HZ to 100:
:: <code>#define HZ 100</code>
:Then recompile 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.

* Omar Yasin: Worked on my {{R52}}, thanks.

* [[User:Thinker|Thinker]]: In modern kernels this constant is in the kernel configuration {{kernelconf|CONFIG_HZ|Processor type and features||Timer Frequency|||||}}.

===Prevent idling===

Indirectly avoid power saving states by making sure the CPU is rarely idle:

* Paul RIVIER: Here is a really simple workaround. C3 / C4 states are mainly called when the cpu freq is higher than required, for example if your cpufreqd is lazy to slow down the frequency but quick to raise it. That is why I use powernowd with the builtin "passive" mode, which is lazy for raising frequency, but quick to go back to the lowest. Now I don't hear them as often as before, as I avoid C3/C4 states at high frequency.

* The problem also occurs on my {{X41}} with 2.6.11. Setting up [[How to make use of Dynamic Frequency Scaling|frequency scaling]] with the <code>ondemand</code> governor makes things a lot better, as the processor does not stay with the maximum frequency when in idle mode. It can be still heard sometimes, though.

* On a {{T43}} the noise was gone after dropping cpufreqd and switching to the ondemand governor - maybe because of the high sampling rate? (used the default: 10ms)

===Change the processor voltage===

Reducing the processor voltage (when possible) may decrease or eliminate the noise. On one ThinkPad {{T43}}, [[Pentium M undervolting and underclocking|undervolting the Pentium M processor]] eliminated the high-pitched noise. Compared to the other solutions this has the benefit of lower power consumption, both due to the undervolting itself and because there is no need to forbid high APCI CPU power saving modes.

==Other solutions==

===Disable UltraBay===
*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 noise. If you have [[ibm-acpi]], do (need a cleaner solution): {{cmduser|echo eject >/proc/acpi/ibm/bay}} .

===Disable IrDA===
*Mike Perry: I was able to cure an intermittent high-pitched whine on both my {{X24}} and {{X40}} by disabling the Infrared port.

===Disable the Linuxant Modem Driver===
*Joern Heissler: I made another experience. I played around with linuxant conexant [[Modem Devices|modem]] drivers. After loading them I got some noise on my {{T42p}}.

===Media Player paused===
*Eilif Muller: On my {{R52}} the high-pitched noises go away if I load XMMS, play something then pause it.
*Jacob: On my {{T43}} DGU it goes away if I open mplayerc.exe and press play then pause it. This is the high-pitched noise that only shows up when I'm on battery.

''I'd guess that the above tip works as when xmms or similar is running, it is uncompressing compressed audio/video, which is a processor intensive action. Keeping this paused means that the app won't 'let go' of the processor, forcing it to stay up and running, which stops it entering the higher powersave modes.''

===Upgrade BIOS===
On a ThinkPad [[X60s]], [[BIOS_Upgrade|upgrading the BIOS]] to version 1.06 eliminated the high pitch noise when running on battery.

===Disable USB===
On one {{T43}} and one {{X60}}, (partially) disabling USB using {{cmdroot|rmmod uhci_hcd}} significantly reduced the noise.

Problem with high power drain in ACPI sleep

2006-06-14T01:28:05Z

Ccshan: /* For ThinkPads with Radeon graphic chips */ Link to latest patch; remove "radeon_" from "radeon_force_sleep" kernel-module parameter

{| width="100%"
|style="vertical-align:top;padding-right:20px;width:10px;white-space:nowrap;" | __TOC__
|style="vertical-align:top" |
==Problem description==
Several people realized that their ThinkPads eat up too much power while suspended to ram via ACPI. Compared to APM suspend to ram the power drain is experienced to be about 10 times as high, 2-5 Watts. This empties the battery within one or two days.
|}

==Affected Models==
{| border="1" cellspacing="0" cellpadding="2" style="float:right;margin-left:20px;"
|-
! style="vertical-align:top;background-color:#ffcfbc;" | affected models
! style="vertical-align:top;background-color:#cfefcf;" | unaffected models
|-
| style="vertical-align:top;background-color:#fff0e0;" |
* {{R32}}
** 2658-BQG
* {{R40}}
** 2722-3GG
** 2722-5MG
** 2722-B3G
** 2722-CDG
** 2897-GWU
** 2722-6YU
** 2722-CDG
* {{R50}}
** 1829-7RG
** 1829-6DM
** 1836-3SU
* {{R51}}
** 1829-9MG
** 1829-EHG
** 1829-R6G
** 1830-DG4
** 1836-Q6U
* {{T23}}
**2647-???
* {{T30}}
** 2366-81A
** 2366-97U
** 2366-FBU
** 2366-96G
*{{T40}}
**2373-19G
**2373-22G
**2373-42G
**2373-75G
**2373-82U
**2373-92U
**2373-A1U
**2373-MU3
*{{T40p}}
**2373-G1U
**2373-G3U
**2373-G3G
**2373-G1G
**2373-G5G
* {{T41}}
**2379-DJU
**2373-3KG
**2373-9HU
**2373-4FG
**2373-4PG
**2373-1FG
**2373-2FG
**2373-2GG
**2373-6U4
**2373-7JU
**2373-CY0
**2373-TG5
**2373-3HM
**2373-4GU
* {{T41p}}
**2373-9FU
* {{T42}}
**2373-C19
**2373-CTO
**2378-DTU
**2378-DUU
**2378-XXE
**2378-R4U
**2373-FWG
**2374-ZEP
**2373-F2G
**2373-VUW
**[[2373-6ZG]]
* {{X21}}
**2662-BSG
* {{X32}}
**2884-A3U
*{{X41T}}
** 1869-5CU
| style="vertical-align:top;background-color:#e9f9e9;" |
*[[:Category:A22m | A22m]]
**2628
*[[:Category:A31 | A31]]
**2652-D5G
*[[:Category:R50p | R50p]]
*[[:Category:R52 | R52]]
**1858-6MM
*[[:Category:T41 | T41]]
**2373-GEU
*[[:Category:T41p | T41p]]
**2373-GKG
**2373-GGG
**[[2373-GHG]]
*[[:Category:T42 | T42]]
**[[2373-M1G]]
**[[2373-WBZ]]
**[[2373-F7G]]
**[[2378-DXU]]
**[[2378-FVU]]
**[[2378-RTU]]
**[[2378-RRU]]
*[[:Category:T42p | T42p]]
**[[2373-HTG]]
**[[2373-W6M]]
**[[2373-GTG]]
**[[2373-GXG]]
**2373-KXM
*[[:Category:T43 | T43]]
**[[2668-W12]]
*[[:Category:T43p | T43p]]
**[[2668-G2G]]
*[[:Category:X40 | X40]]
**2371
|}
*Different symptoms have been reported for different models. In some models the origin of the power drain is obvious ([[Problem with LCD backlight remaining on during ACPI sleep|backlight on during suspend]]), in other models there is no obvious reason.

*On some models/configurations the higher power drain couldn't even be realized or was at least significantly lower.

*The T4x ThinkPad series and other Radeon based models suspend to ram just fine, and there are no components that are obviously left powered up. The [[UltraBay]] and network light is on, but that is the same under windows (but under APM sleep to RAM those lights are OFF). For these models the higher power drain is caused by a driver problem and can be fixed in software. This fix has not yet made its way into the official kernel (as of linux 2.6.12).

The table on the right gives an overview of the models suffering from the mysterious power drain. To find out about your model, you may use the following [[ACPI sleep power drain test script | script]]. It creates a file {{path|/var/log/battery.log}} which will tell you if you are affected or not.

==Affected Operating Systems==
*Linux, all flavours.
*Windows, for some models as well (only when using non-IBM drivers).
*FreeBSD (on the A22M)

==Status==
*The cause of the mysterious power drain is the Radeon GPU, which requires extra steps to suspend properly. Unfortunately, this fix might break non-ThinkPad machines and therefore is not yet in the official kernel sources.
*The official bugzilla entry for the radeon suspend issue is in the [http://bugme.osdl.org/show_bug.cgi?id=3022 OSDL Bugzilla]. There you can find a patch which will solve the power drain issue.
{{WARN|This solution enables doing suspend-to-D2 on non-PPC-machines, which is not properly documented! Be careful and have a look at the discussion for kernel bug 3022 (see above) before applying the patch. By default, the patch enables the suspend-to-D2 only on machines where it is known to work. This behaviour can be overridden with a module option.}}
{{NOTE|This solution is on its way for inclusion into the mainline Linux kernel, but the whitelist required for its inclusion needs your help. Please send mail to ''patroclo7 at gmail.com'' with the output of '''lspci -d "1002:*" -vn''' on affected machines ''only''. Refer to [http://thread.gmane.org/gmane.linux.hardware.thinkpad/25355 the linux-thinkpad ML post requesting this information] for more information. This is mostly urgent if you happen to own an X21 or a R50.}}
*Most certainly, the DSDT is not at fault. (Interesting to note: The DSDT from BIOS 3.13 (Nov 04) for the T42p compiles without bugs.)
*Some additional power savings can be achieved by turning off the wake-on-lan ({{cmdroot|ethtool -s eth0 wol d}}). The power drain of the wol feature is far smaller than the radeon bug, but can be noticeable.

==Solutions==
===For ThinkPads with Radeon graphic chips===
You must use a patched version of the radeon frame buffer, even if you are only interested in using the X window system. This modified radeon frame buffer then suspends the radeon chip correctly during ACPI sleep. This patch is not yet in the official (kernel.org) kernels.

The [http://bugme.osdl.org/attachment.cgi?id=8220&action=view patch] contains a list of ThinkPads where it is known to work, and by default only activates on these machines. If you think that your computer would profit from the patch as well, you can force it by including the module parameter {{bootparm|force_sleep|1}}. If it doesn't work this can result in system hangs.

====Technical Background====
The patch removes the CONFIG_PPC_PMAC condition for enabling D2 sleep in {{path|drivers/video/aty/radeon_pm.c}} as discussed in [http://bugme.osdl.org/show_bug.cgi?id=3022 kernel bug 3022].

====Fedora Core====
* Fedora Core 4: Fedora ships a patched radeon frame buffer (radeonfb.ko), but you must enable it yourself. {{Fedora}} compiles it as a module rather than including it in the kernel, therefore you cannot activate it at boot time without a custom initrd. You must arrange for the module to be loaded before X starts (for example, using an init script).
* Fedora Core 3: this is also true for updated kernels (at least for kernel-2.6.12-1.1376_FC3) but '''not''' for the initially shipped version.

There are precompiled patched kernels [http://www.sas.upenn.edu/~vbraun/computing/T41/kernel.html available] as well, that do not need an initrd modification:
*[http://carrot.hep.upenn.edu/~vbraun/kernel-T4x/i386/kernel-T4x-2.6.11.11-26.i386.rpm linux 2.6.11 for Fedora Core 3]
*[http://carrot.hep.upenn.edu/~vbraun/kernel-T4x/i386/kernel-T4x-2.6.12.2-2.i386.rpm linux 2.6.12 for Fedora Core 4]
These kernels contain additional ThinkPad-related patches, including [[Software Suspend 2]] and trackpoint support. Suspend to disk and suspend to ram should work with them. If your ThinkPad model is not yet whitelisted in the patch, you might have to enable the radeon fix by including the parameter {{bootparm|video|2=radeonfb:force_sleep}} on the kernel command line.

If you try, please send the result (hang yes/no, battery drain yes/no) with the precise model number (i.e. IBM ThinkPad T41 2379-DJU) to <tt>vbraun at physics dot upenn dot edu</tt>, it would be nice if your subject line would include "RADEONFB:" to make sure that I do not miss any emails.

=====testing radeonfb without changing initrd=====
If you want to try the radeon frame buffer, you can enable it as follows:
*First, switch to a console ({{key|Ctrl}}{{key|Alt}}{{key|F1}}) and log in as root.
*Stop X: {{cmdroot|init 3}}
*Now you can load the module: {{cmdroot|1=modprobe radeonfb force_sleep=1}}
*Finally, resume X: {{cmdroot|init 5}}

=====including radeonfb into your initrd=====
As an alternative you can build your customized initrd. This is as simple as running
:{{cmdroot|1=mkinitrd --with=radeonfb /boot/<name-of-your-new-initrd> `uname -r`}}
and replacing the initrd in {{path|/boot/grub/grub.conf}} with your new one. You also need to add the kernel command line argument {{bootparm|video|2=radeonfb:force_sleep}}.

====Gentoo====
After installing the patch on {{Gentoo}} (it works fine with gentoo-sources: {{cmdroot|cd /usr/src/linux/drivers/video/aty}}, and execute {{cmdroot|patch -p4 <patchname>}}, then recompile the kernel), one needs to add {{bootparm|video|radeonfb:force_sleep}} to the kernel parameters.

====Another possible solution====
It is possible that [[radeontool]] will help some people with this case.
(simply run radeontool light off before suspend and radeontool light on after resume).
A radeontool patch for freebsd is here: http://www.init-main.com/radeontool.patch (by Takanori Watanabe).

===For models without radeon graphics===
The Problem seems to be solved when you use the [http://www.srcf.ucam.org/~mjg59/vbetool/ vbetool] to turn the LCD off before suspending ...
:{{cmdroot|vbetool dpms off}}
and turning it on afterwards again...
:{{cmdroot|vbetool dpms on}}
You have to change to a normal console before turning the LCD off.
Additionally you have to deactivate the Wake-On-Lan feature like mentioned above ...
:{{cmdroot|ethtool -s eth0 wol d}}
With these commands used together the "testing script" reports no high power drain while suspending.