openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

ACPI: ibm-acpi: document fan control 

This patch documents the ThinkPad fan control strategies.  Source of the
data:

0. ibm-acpi source
1. DSDTs for various ThinkPads (770, X31, X40, X41, T43, A21m, T22)
2. http://thinkwiki.org/wiki/Embedded_Controller_Firmware#Firmware_Issues
3. http://thinkwiki.org/wiki/How_to_control_fan_speed
4. Various threads about windows fan control utilities in thinkpads.com

Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
This commit is contained in:
Henrique de Moraes Holschuh 2006-11-24 11:47:11 -02:00 committed by Len Brown
parent 18ad7996e1
commit a8b7a6626d
1 changed files with 108 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

110
drivers/acpi/ibm_acpi.c
View File

@ -205,7 +205,7 @@ IBM_HANDLE(led, ec, "SLED", /* 570 */
IBM_HANDLE(beep, ec, "BEEP"); /* all except R30, R31 */
IBM_HANDLE(ecrd, ec, "ECRD"); /* 570 */
IBM_HANDLE(ecwr, ec, "ECWR"); /* 570 */
IBM_HANDLE(fans, ec, "FANS"); /* X31, X40 */
IBM_HANDLE(fans, ec, "FANS"); /* X31, X40, X41 */
IBM_HANDLE(gfan, ec, "GFAN", /* 570 */
"\\FSPD", /* 600e/x, 770e, 770x */
@ -231,6 +231,106 @@ struct ibm_thermal_sensors_struct {
s32 temp[IBMACPI_MAX_THERMAL_SENSORS];
};
/*
* FAN ACCESS MODES
*
* IBMACPI_FAN_RD_ACPI_GFAN:
* ACPI GFAN method: returns fan level
*
* see IBMACPI_FAN_WR_ACPI_SFAN
* EC 0x2f not available if GFAN exists
*
* IBMACPI_FAN_WR_ACPI_SFAN:
* ACPI SFAN method: sets fan level, 0 (stop) to 7 (max)
*
* EC 0x2f might be available *for reading*, but never for writing.
*
* IBMACPI_FAN_WR_TPEC:
* ThinkPad EC register 0x2f (HFSP): fan control loop mode Supported
* on almost all ThinkPads
*
* Fan speed changes of any sort (including those caused by the
* disengaged mode) are usually done slowly by the firmware as the
* maximum ammount of fan duty cycle change per second seems to be
* limited.
*
* Reading is not available if GFAN exists.
* Writing is not available if SFAN exists.
*
* Bits
* 7 automatic mode engaged;
* (default operation mode of the ThinkPad)
* fan level is ignored in this mode.
* 6 disengage mode (takes precedence over bit 7);
* not available on all thinkpads. May disable
* the tachometer, and speeds up fan to 100% duty-cycle,
* which speeds it up far above the standard RPM
* levels. It is not impossible that it could cause
* hardware damage.
* 5-3 unused in some models. Extra bits for fan level
* in others, but still useless as all values above
* 7 map to the same speed as level 7 in these models.
* 2-0 fan level (0..7 usually)
* 0x00 = stop
* 0x07 = max (set when temperatures critical)
* Some ThinkPads may have other levels, see
* IBMACPI_FAN_WR_ACPI_FANS (X31/X40/X41)
*
* FIRMWARE BUG: on some models, EC 0x2f might not be initialized at
* boot. Apparently the EC does not intialize it, so unless ACPI DSDT
* does so, its initial value is meaningless (0x07).
*
* For firmware bugs, refer to:
* http://thinkwiki.org/wiki/Embedded_Controller_Firmware#Firmware_Issues
*
* ----
*
* ThinkPad EC register 0x84 (LSB), 0x85 (MSB):
* Main fan tachometer reading (in RPM)
*
* This register is present on all ThinkPads with a new-style EC, and
* it is known not to be present on the A21m/e, and T22, as there is
* something else in offset 0x84 according to the ACPI DSDT. Other
* ThinkPads from this same time period (and earlier) probably lack the
* tachometer as well.
*
* Unfortunately a lot of ThinkPads with new-style ECs but whose firwmare
* was never fixed by IBM to report the EC firmware version string
* probably support the tachometer (like the early X models), so
* detecting it is quite hard. We need more data to know for sure.
*
* FIRMWARE BUG: always read 0x84 first, otherwise incorrect readings
* might result.
*
* FIRMWARE BUG: when EC 0x2f bit 6 is set (disengaged mode), this
* register is not invalidated in ThinkPads that disable tachometer
* readings. Thus, the tachometer readings go stale.
*
* For firmware bugs, refer to:
* http://thinkwiki.org/wiki/Embedded_Controller_Firmware#Firmware_Issues
*
* IBMACPI_FAN_WR_ACPI_FANS:
* ThinkPad X31, X40, X41. Not available in the X60.
*
* FANS ACPI handle: takes three arguments: low speed, medium speed,
* high speed. ACPI DSDT seems to map these three speeds to levels
* as follows: STOP LOW LOW MED MED HIGH HIGH HIGH HIGH
* (this map is stored on FAN0..FAN8 as "0,1,1,2,2,3,3,3,3")
*
* The speeds are stored on handles
* (FANA:FAN9), (FANC:FANB), (FANE:FAND).
*
* There are three default speed sets, acessible as handles:
* FS1L,FS1M,FS1H; FS2L,FS2M,FS2H; FS3L,FS3M,FS3H
*
* ACPI DSDT switches which set is in use depending on various
* factors.
*
* IBMACPI_FAN_WR_TPEC is also available and should be used to
* command the fan. The X31/X40/X41 seems to have 8 fan levels,
* but the ACPI tables just mention level 7.
*/
enum fan_status_access_mode {
IBMACPI_FAN_NONE = 0, /* No fan status or control */
IBMACPI_FAN_RD_ACPI_GFAN, /* Use ACPI GFAN */
@ -1722,7 +1822,7 @@ static int fan_init(void)
/* all other models implement TP EC 0x2f control */
if (fans_handle) {
/* X31, X40 */
/* X31, X40, X41 */
fan_control_access_mode =
IBMACPI_FAN_WR_ACPI_FANS;
fan_control_commands |=
@ -1742,6 +1842,9 @@ static int fan_get_status(u8 *status)
{
u8 s;
/* TODO:
* Add IBMACPI_FAN_RD_ACPI_FANS ? */
switch (fan_status_access_mode) {
case IBMACPI_FAN_RD_ACPI_GFAN:
/* 570, 600e/x, 770e, 770x */
@ -1950,6 +2053,9 @@ static int fan_write_cmd_speed(const char *cmd, int *rc)
{
int speed;
/* TODO:
* Support speed <low> <medium> <high> ? */
if (sscanf(cmd, "speed %d", &speed) != 1)
return 0;