[PATCH 13/21] ACPI: ibm-acpi: fix and extend fan control functions

Henrique de Moraes Holschuh
2006-11-25T20:46:14Z

From: Henrique de Moraes Holschuh <hmh@hmh.eng.br>

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: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
---

Documentation/ibm-acpi.txt | 65 +++++++++++++++++++++++++++++++-------------
drivers/acpi/ibm_acpi.c | 39 +++++++++++++++++++++++---
2 files changed, 80 insertions(+), 24 deletions(-)

diff --git a/Documentation/ibm-acpi.txt b/Documentation/ibm-acpi.txt
index 333b8eb..cbd3a60 100644
--- a/Documentation/ibm-acpi.txt
+++ b/Documentation/ibm-acpi.txt
@@ -571,27 +571,57 @@ directly accesses hardware registers and
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
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
---------------------------------------
diff --git a/drivers/acpi/ibm_acpi.c b/drivers/acpi/ibm_acpi.c
index 001a5e9..7ea4a26 100644
--- a/drivers/acpi/ibm_acpi.c
+++ b/drivers/acpi/ibm_acpi.c
@@ -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 cha
{
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)