Difference between revisions of "Patch for controlling fan speed"

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==Overview==
 
==Overview==
  
−
This patch extends the <tt>ibm-acpi</tt> Linux kernel module to control fan speed. It can be used to reduce [[Problem with fan noise|fan noise]] and power consumption.
+
{{NOTE|The patch is no longer necessary with kernel > 2.6.10. After opening a root shell with '''$sudo -s''', you should be able to run al of these commands. See: [[How_to_control_fan_speed|How to control fan speed]]}}
 +
 
 +
 
 +
This patch extends the [[ibm-acpi]] Linux kernel module to control fan speed. It can be used to reduce [[Problem with fan noise|fan noise]] (both speed and pulsing) and to decrease fan power consumption.
  
 
When this patch is applied and the <tt>ibm-acpi</tt> module is loaded with the <tt>experimental=1</tt> module parameter, the following new capabilities are added to {{path|/proc/acpi/ibm/fan}}:
 
When this patch is applied and the <tt>ibm-acpi</tt> module is loaded with the <tt>experimental=1</tt> module parameter, the following new capabilities are added to {{path|/proc/acpi/ibm/fan}}:
−
* {{cmdroot|echo LEVEL > /proc/acpi/ibm/fan}} sets a fan speed level between 0 and 7, where <tt>LEVEL</TT>=0 means fan off and <tt>LEVEL</tt>=7 is the fastest speed.
+
* {{cmdroot|echo level LEVEL > /proc/acpi/ibm/fan}} sets a fan speed level between 0 and 7, where <tt>LEVEL</TT>=0 means fan off and <tt>LEVEL</tt>=7 is the fastest speed.
−
* {{cmdroot|echo auto > /proc/acpi/ibm/fan}} tells the embedded controller to set the fan speed automatically according to system temperatures (this is the default).
+
* {{cmdroot|echo level auto > /proc/acpi/ibm/fan}} tells the embedded controller to set the fan speed automatically according to system temperatures (this is the default).
 +
* {{cmdroot|echo level disengaged > /proc/acpi/ibm/fan}} tells the embedded controller to disengage fan speed control (see specs below).
 
* {{cmdroot|cat /proc/acpi/ibm/fan}} shows the current fan level (in addition to the fan speed in RPM).
 
* {{cmdroot|cat /proc/acpi/ibm/fan}} shows the current fan level (in addition to the fan speed in RPM).
  
−
This patch is best used with a program that monitors system temperature and sets the fan speed accordingly. The [[ACPI fan control script|current scripts for fan control]] could serve as the basis of such program.
+
For example:
 +
 
 +
'''#cat /proc/acpi/ibm/fan'''
 +
status:        enabled
 +
level:          auto
 +
speed:          4219
 +
commands:      enable, disable, level <level>
 +
                (<level> is 0-7, auto or disengaged)
 +
 +
'''#echo level 2 > /proc/acpi/ibm/fan'''
 +
 +
'''#cat /proc/acpi/ibm/fan'''
 +
status:        enabled
 +
level:          2
 +
speed:          3142
 +
commands:      enable, disable, level <level>
 +
                (<level> is 0-7, auto or disengaged)
 +
 
 +
This patch is best used with an [[ACPI fan control script#Variable speed control scripts|ACPI fan control script]] that monitors system temperature and sets the fan speed accordingly.
  
 
{{WARN|Overriding the system's automatic temperature control may cause permanent hardware damage. Even when using temperature monitoring software, it is not clear whether the software can access all temperature sensor accessible to the embedded controller and understand them correctly. Moreover, this patch relies on an undocumented hardware interface, and may thus have arbitrary effects (especially on models it wasn't tested on).}}
 
{{WARN|Overriding the system's automatic temperature control may cause permanent hardware damage. Even when using temperature monitoring software, it is not clear whether the software can access all temperature sensor accessible to the embedded controller and understand them correctly. Moreover, this patch relies on an undocumented hardware interface, and may thus have arbitrary effects (especially on models it wasn't tested on).}}
  
−
==Models on which this patch works==
+
==The patch==
 +
 
 +
===for ibm-acpi 0.11===
 +
{{CodeRef|ibm-acpi-0.11-2.6.13-fan.patch}}
  
−
* ThinkPad {{T43}}, {{T43p}}<br />(levels 1-2 = ~3300RPM, level 3-5 = ~4100RPM, level 6-7 = ~4700 RPM)
+
This also includes a minor fix (rename of <tt>device_add</tt>) to make [[ibm-acpi]] 0.11 compile on kernel 2.6.13.
  
−
Probably many other models; please update this page with your results.
+
===for ibm-acpi 0.12a as found in kernels 2.6.14 and 2.6.17===
  
−
I can confirm that it works on Thinkpad {{T43}} here. However after
+
A slightly modified version which also keeps the lines in the format expected by the gkrellm plugin.
−
applying the patch, the fan speed monitor of gkrellm 2.2.7 cannot read
 
−
value correctly. Maybe we gkrellm is reading the second line for speed
 
−
but instead find the line for level, so it got confused? Would it be possible to interchange the lines so that speed still appears in the  
 
−
second line and level appears in the third instead? I'm no coder, just
 
−
a suggestion to improve the patch.
 
−
--Jiang
 
  
−
==Models on which this patch doesn't work==
+
{{CodeRef|ibm-acpi-0.12a-2.6.14-fan.patch}}
  
−
* ThinkPad {{560}}, {{600E}}, {{600X}}, {{770E}}, {{770X}} (these use a different fan control interface)
+
{{CodeRef|ibm-acpi-0.12a-2.6.17-fan.patch}}
  
−
==The patch==
+
{{NOTE|In order to patch the ibm_acpi.c file you have to issue the following command: <code>patch -p0 -l < fanpatch</code>. The '-l' option is important because the patch pasted here doesn't have any tabs any more. Another piece of advice: Always try to patch the files first before really patching them. That is done by adding --dry-run to the command.}}
 +
 
 +
===Ideas for improvement===
  
−
This also includes a minor fix (rename of <tt>device_add</tt>) to make ibm-acpi 0.11 compile on kernel 2.6.13.
+
* When fan speed is controlled from userspace (e.g., by the [[ACPI fan control script#Variable speed control scripts|ACPI fan control scripts]]), the userspace component may die (for whatever reason) leaving the fan at a low speed, potentially leading to damage. We can add a watchdog to the kernel component, which resets the fan to Embedded Controller control (<tt>leve: auto</tt>) if {{path|/proc/acpi/ibm/fan}} was not written to for ''N'' seconds.
  
−
<pre>
+
==Alternative methods and hardware specs==
−
--- ibm-acpi-0.11-orig/ibm_acpi.c 2005-03-17 12:06:16.000000000 +0200
 
−
+++ ibm-acpi-0.11/ibm_acpi.c 2005-10-24 12:56:44.000000000 +0200
 
−
@@ -1488,11 +1488,16 @@ static int fan_read(char *p)
 
−
} else {
 
−
/* all except 570, 600e/x, 770e, 770x */
 
−
if (!acpi_ec_read(fan_status_offset, &status))
 
−
len += sprintf(p + len, "status:\t\tunreadable\n");
 
−
- else
 
−
+ else {
 
−
len += sprintf(p + len, "status:\t\t%s\n",
 
−
-       enabled(status, 7));
 
−
+       status ? "enabled" : "disabled");
 
−
+ if (status & 0x80)
 
−
+ len += sprintf(p + len, "level:\t\tauto\n");
 
−
+ else
 
−
+ len += sprintf(p + len, "level:\t\t%d\n", status);
 
−
+ }
 
−
 
−
if (!acpi_ec_read(fan_rpm_offset,    &lo) ||
 
−
    !acpi_ec_read(fan_rpm_offset + 1, &hi))
 
−
len += sprintf(p + len, "speed:\t\tunreadable\n");
 
−
@@ -1506,9 +1511,10 @@ static int fan_read(char *p)
 
−
len += sprintf(p + len, "commands:\tlevel <level>"
 
−
      " (<level> is 0-7)\n");
 
−
if (!gfan_handle)
 
−
/* all except 570, 600e/x, 770e, 770x */
 
−
- len += sprintf(p + len, "commands:\tenable, disable\n");
 
−
+ len += sprintf(p + len, "commands:\tenable, disable, level <level>\n"
 
−
+                 "        \t(<level> is 0-7 or auto)\n");
 
−
if (fans_handle)
 
−
/* X31, X40 */
 
−
len += sprintf(p + len, "commands:\tspeed <speed>"
 
−
      " (<speed> is 0-65535)\n");
 
−
@@ -1528,17 +1534,24 @@ static int fan_write(char *buf)
 
−
/* 570, 770x-JL */
 
−
if (!acpi_evalf(sfan_handle, NULL, NULL, "vd", level))
 
−
return -EIO;
 
−
} else if (!gfan_handle &&
 
−
-   strlencmp(cmd, "enable") == 0) {
 
−
+   ( (strlencmp(cmd, "enable") == 0) ||
 
−
+     (strlencmp(cmd, "level auto") == 0) ) ) {
 
−
/* all except 570, 600e/x, 770e, 770x */
 
−
if (!acpi_ec_write(fan_status_offset, 0x80))
 
−
return -EIO;
 
−
} else if (!gfan_handle &&
 
−
  strlencmp(cmd, "disable") == 0) {
 
−
/* all except 570, 600e/x, 770e, 770x */
 
−
if (!acpi_ec_write(fan_status_offset, 0x00))
 
−
return -EIO;
 
−
+ } else if (!gfan_handle &&
 
−
+     sscanf(cmd, "level %d", &level) == 1 &&
 
−
+     level >=0 && level <= 7) {
 
−
+ /* all except 570, 600e/x, 770e, 770x */
 
−
+ if (!acpi_ec_write(fan_status_offset, level))
 
−
+ return -EIO;
 
−
} else if (fans_handle &&
 
−
    sscanf(cmd, "speed %d", &speed) == 1 &&
 
−
    speed >= 0 && speed <= 65535) {
 
−
/* X31, X40 */
 
−
@@ -1751,9 +1764,9 @@ static int __init setup_notify(struct ib
 
−
 
−
return 0;
 
−
}
 
−
 
−
-static int device_add(struct acpi_device *device)
 
−
+static int ibmacpi_device_add(struct acpi_device *device)
 
−
{
 
−
return 0;
 
−
}
 
−
 
−
@@ -1769,9 +1782,9 @@ static int __init register_driver(struct
 
−
 
−
memset(ibm->driver, 0, sizeof(struct acpi_driver));
 
−
sprintf(ibm->driver->name, "%s/%s", IBM_NAME, ibm->name);
 
−
ibm->driver->ids = ibm->hid;
 
−
- ibm->driver->ops.add = &device_add;
 
−
+ ibm->driver->ops.add = &ibmacpi_device_add;
 
−
 
−
ret = acpi_bus_register_driver(ibm->driver);
 
−
if (ret < 0) {
 
−
printk(IBM_ERR "acpi_bus_register_driver(%s) failed: %d\n",
 
−
</pre>
 
  
−
==Hardware spec==
+
See [[How to control fan speed]].
  
−
The patch relies on the following hardware behavior, discovered experimentally on a ThinkPad {{T43}}.
+
==Supported models==
  
−
  ACPI DSDT register _SB.PCI0.LPC.EC.HFSP (8 bits, offset 0x2F in the EmbeddedController address space):
+
See [[How to control fan speed]].
−
 
−
  7 6 5 4 3 2 1 0
 
−
  | ? ? |  \___/
 
−
  |    |    |
 
−
  |    |    +------ manual fan speed level (0=disable, 1=min, ..., 7=max)
 
−
  |    \------------ no effect
 
−
  \------------------ automatic fan speed control (1=enable, overrides manual)
 
  
 
[[Category:Patches]]
 
[[Category:Patches]]

Latest revision as of 02:08, 24 March 2008

Overview

NOTE!
The patch is no longer necessary with kernel > 2.6.10. After opening a root shell with $sudo -s, you should be able to run al of these commands. See: How to control fan speed


This patch extends the ibm-acpi Linux kernel module to control fan speed. It can be used to reduce fan noise (both speed and pulsing) and to decrease fan power consumption.

When this patch is applied and the ibm-acpi module is loaded with the experimental=1 module parameter, the following new capabilities are added to /proc/acpi/ibm/fan:

  • # echo level LEVEL > /proc/acpi/ibm/fan sets a fan speed level between 0 and 7, where LEVEL=0 means fan off and LEVEL=7 is the fastest speed.
  • # echo level auto > /proc/acpi/ibm/fan tells the embedded controller to set the fan speed automatically according to system temperatures (this is the default).
  • # echo level disengaged > /proc/acpi/ibm/fan tells the embedded controller to disengage fan speed control (see specs below).
  • # cat /proc/acpi/ibm/fan shows the current fan level (in addition to the fan speed in RPM).

For example: 

#cat /proc/acpi/ibm/fan
status:         enabled
level:          auto
speed:          4219
commands:       enable, disable, level <level>
                (<level> is 0-7, auto or disengaged)

#echo level 2 > /proc/acpi/ibm/fan

#cat /proc/acpi/ibm/fan
status:         enabled
level:          2
speed:          3142
commands:       enable, disable, level <level>
                (<level> is 0-7, auto or disengaged)

This patch is best used with an ACPI fan control script that monitors system temperature and sets the fan speed accordingly.

ATTENTION!
Overriding the system's automatic temperature control may cause permanent hardware damage. Even when using temperature monitoring software, it is not clear whether the software can access all temperature sensor accessible to the embedded controller and understand them correctly. Moreover, this patch relies on an undocumented hardware interface, and may thus have arbitrary effects (especially on models it wasn't tested on).

The patch

for ibm-acpi 0.11

ibm-acpi-0.11-2.6.13-fan.patch (download)

This also includes a minor fix (rename of device_add) to make ibm-acpi 0.11 compile on kernel 2.6.13.

for ibm-acpi 0.12a as found in kernels 2.6.14 and 2.6.17

A slightly modified version which also keeps the lines in the format expected by the gkrellm plugin.

ibm-acpi-0.12a-2.6.14-fan.patch (download)

ibm-acpi-0.12a-2.6.17-fan.patch (download)

NOTE!
In order to patch the ibm_acpi.c file you have to issue the following command: patch -p0 -l < fanpatch. The '-l' option is important because the patch pasted here doesn't have any tabs any more. Another piece of advice: Always try to patch the files first before really patching them. That is done by adding --dry-run to the command.

Ideas for improvement

  • When fan speed is controlled from userspace (e.g., by the ACPI fan control scripts), the userspace component may die (for whatever reason) leaving the fan at a low speed, potentially leading to damage. We can add a watchdog to the kernel component, which resets the fan to Embedded Controller control (leve: auto) if /proc/acpi/ibm/fan was not written to for N seconds.

Alternative methods and hardware specs

See How to control fan speed.

Supported models

See How to control fan speed.

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