Commit a12095c2 authored by Henrique de Moraes Holschuh's avatar Henrique de Moraes Holschuh Committed by Len Brown
Browse files

ACPI: ibm-acpi: fix and extend fan control functions 



This patch extend fan control functions, implementing enable/disable for
all write access modes, implementing level control for all level-capable
write access modes.

The patch also updates the documentation, explaining levels auto and
disengaged.

ABI changes:
	1. Support level 0 as an equivalent to disable
	2. Add support for level auto and level disengaged when doing
	   EC 0x2f fan control
	3. Support enable/disable for all level-based write access modes
	4. Add support for level command on FANS thinkpads, as per
	   thinkwiki reports

Signed-off-by: default avatarHenrique de Moraes Holschuh <hmh@hmh.eng.br>
parent 1c6a334e

Documentation/ibm-acpi.txt

+46 −19
Original line number Diff line number Diff line
@@ -571,27 +571,57 @@ directly accesses hardware registers and may not work as expected. USE 
WITH CAUTION! To use this feature, you need to supply the

experimental=1 parameter when loading the module.



This feature attempts to show the current fan speed. The speed is read

directly from the hardware registers of the embedded controller. This

is known to work on later R, T and X series ThinkPads but may show a

bogus value on other models.

This feature attempts to show the current fan speed, control mode and

other fan data that might be available.  The speed is read directly

from the hardware registers of the embedded controller.  This is known

to work on later R, T and X series ThinkPads but may show a bogus

value on other models.



Most ThinkPad fans work in "levels".  Level 0 stops the fan.  The higher

the level, the higher the fan speed, although adjacent levels often map

to the same fan speed.  7 is the highest level, where the fan reaches

the maximum recommended speed.  Level "auto" means the EC changes the

fan level according to some internal algorithm, usually based on

readings from the thermal sensors.  Level "disengaged" means the EC

disables the speed-locked closed-loop fan control, and drives the fan as

fast as it can go, which might exceed hardware limits, so use this level

with caution.



The fan usually ramps up or down slowly from one speed to another,

and it is normal for the EC to take several seconds to react to fan

commands.



The fan may be enabled or disabled with the following commands:



	echo enable  >/proc/acpi/ibm/fan

	echo disable >/proc/acpi/ibm/fan



Placing a fan on level 0 is the same as disabling it.  Enabling a fan

will try to place it in a safe level if it is too slow or disabled.



WARNING WARNING WARNING: do not leave the fan disabled unless you are

monitoring the temperature sensor readings and you are ready to enable

it if necessary to avoid overheating.

monitoring all of the temperature sensor readings and you are ready to

enable it if necessary to avoid overheating.



An enabled fan in level "auto" may stop spinning if the EC decides the

ThinkPad is cool enough and doesn't need the extra airflow.  This is

normal, and the EC will spin the fan up if the varios thermal readings

rise too much.



On the X40, this seems to depend on the CPU and HDD temperatures.

Specifically, the fan is turned on when either the CPU temperature

climbs to 56 degrees or the HDD temperature climbs to 46 degrees.  The

fan is turned off when the CPU temperature drops to 49 degrees and the

HDD temperature drops to 41 degrees.  These thresholds cannot

currently be controlled.



The fan level can be controlled with the command:



The fan only runs if it's enabled *and* the various temperature

sensors which control it read high enough. On the X40, this seems to

depend on the CPU and HDD temperatures. Specifically, the fan is

turned on when either the CPU temperature climbs to 56 degrees or the

HDD temperature climbs to 46 degrees. The fan is turned off when the

CPU temperature drops to 49 degrees and the HDD temperature drops to

41 degrees. These thresholds cannot currently be controlled.

	echo 'level <level>' > /proc/acpi/ibm/thermal



Where <level> is an integer from 0 to 7, or one of the words "auto"

or "disengaged" (without the quotes).  Not all ThinkPads support the

"auto" and "disengaged" levels.



On the X31 and X40 (and ONLY on those models), the fan speed can be

controlled to a certain degree. Once the fan is running, it can be
@@ -604,12 +634,9 @@ about 3700 to about 7350. Values outside this range either do not have 
any effect or the fan speed eventually settles somewhere in that

range. The fan cannot be stopped or started with this command.



On the 570, temperature readings are not available through this

feature and the fan control works a little differently. The fan speed

is reported in levels from 0 (off) to 7 (max) and can be controlled

with the following command:



	echo 'level <level>' > /proc/acpi/ibm/thermal

The ThinkPad's ACPI DSDT code will reprogram the fan on its own when

certain conditions are met.  It will override any fan programming done

through ibm-acpi.



EXPERIMENTAL: WAN -- /proc/acpi/ibm/wan

---------------------------------------

drivers/acpi/ibm_acpi.c

+34 −5
Original line number Diff line number Diff line
@@ -1833,10 +1833,13 @@ static int fan_init(void) 
				    IBMACPI_FAN_WR_ACPI_FANS;

				fan_control_commands |=

				    IBMACPI_FAN_CMD_SPEED |

				    IBMACPI_FAN_CMD_LEVEL |

				    IBMACPI_FAN_CMD_ENABLE;

			} else {

				fan_control_access_mode = IBMACPI_FAN_WR_TPEC;

				fan_control_commands |= IBMACPI_FAN_CMD_ENABLE;

				fan_control_commands |=

				    IBMACPI_FAN_CMD_LEVEL |

				    IBMACPI_FAN_CMD_ENABLE;

			}

		}

	}
@@ -1948,9 +1951,20 @@ static int fan_read(char *p) 
		len += sprintf(p + len, "status:\t\tnot supported\n");

	}



	if (fan_control_commands & IBMACPI_FAN_CMD_LEVEL)

		len += sprintf(p + len, "commands:\tlevel <level>"

			       " (<level> is 0-7)\n");

	if (fan_control_commands & IBMACPI_FAN_CMD_LEVEL) {

		len += sprintf(p + len, "commands:\tlevel <level>");



		switch (fan_control_access_mode) {

		case IBMACPI_FAN_WR_ACPI_SFAN:

			len += sprintf(p + len, " (<level> is 0-7)\n");

			break;



		default:

			len += sprintf(p + len, " (<level> is 0-7, "

				       "auto, disengaged)\n");

			break;

		}

	}



	if (fan_control_commands & IBMACPI_FAN_CMD_ENABLE)

		len += sprintf(p + len, "commands:\tenable, disable\n");
@@ -1973,6 +1987,17 @@ static int fan_set_level(int level) 
			return -EINVAL;

		break;



	case IBMACPI_FAN_WR_ACPI_FANS:

	case IBMACPI_FAN_WR_TPEC:

		if ((level != IBMACPI_FAN_EC_AUTO) &&

		    (level != IBMACPI_FAN_EC_DISENGAGED) &&

		    ((level < 0) || (level > 7)))

			return -EINVAL;



		if (!acpi_ec_write(fan_status_offset, level))

			return -EIO;

		break;



	default:

		return -ENXIO;

	}
@@ -2060,7 +2085,11 @@ static int fan_write_cmd_level(const char *cmd, int *rc) 
{

	int level;



	if (sscanf(cmd, "level %d", &level) != 1)

	if (strlencmp(cmd, "level auto") == 0)

		level = IBMACPI_FAN_EC_AUTO;

	else if (strlencmp(cmd, "level disengaged") == 0)

		level = IBMACPI_FAN_EC_DISENGAGED;

	else if (sscanf(cmd, "level %d", &level) != 1)

		return 0;



	if ((*rc = fan_set_level(level)) == -ENXIO)

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