Difference between revisions of "Patch for controlling fan speed"
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==Models on which this patch doesn't work== | ==Models on which this patch doesn't work== |
Revision as of 01:02, 26 October 2005
Contents
Overview
This patch extends the ibm-acpi Linux kernel module to control fan speed. It can be used to reduce fan noise and 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 > /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 auto > /proc/acpi/ibm/fan
tells the embedded controller to set the fan speed automatically according to system temperatures (this is the default).# 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 current scripts for fan control could serve as the basis of such program.
Models on which this patch works
Probably many other models; please update this page with your results.
Models on which this patch doesn't work
The patch
This also includes a minor fix (rename of device_add) to make ibm-acpi 0.11 compile on kernel 2.6.13.
--- 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",
Hardware spec
The patch relies on the following hardware behavior, discovered experimentally on a ThinkPad T43.
ACPI DSDT register _SB.PCI0.LPC.EC.HFSP (8 bits, offset 0x2F in the EmbeddedController address space): 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)