diff options
| -rw-r--r-- | drivers/misc/thinkpad_acpi.c | 28 |
1 files changed, 13 insertions, 15 deletions
diff --git a/drivers/misc/thinkpad_acpi.c b/drivers/misc/thinkpad_acpi.c index 1683bfe15b35..4131a7875ad7 100644 --- a/drivers/misc/thinkpad_acpi.c +++ b/drivers/misc/thinkpad_acpi.c @@ -1852,16 +1852,17 @@ static int volume_write(char *buf) * ACPI GFAN method: returns fan level * * see TPACPI_FAN_WR_ACPI_SFAN - * EC 0x2f not available if GFAN exists + * EC 0x2f (HFSP) not available if GFAN exists * * TPACPI_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. + * EC 0x2f (HFSP) might be available *for reading*, but do not use + * it for writing. * * TPACPI_FAN_WR_TPEC: - * ThinkPad EC register 0x2f (HFSP): fan control loop mode Supported - * on almost all ThinkPads + * 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 @@ -1875,12 +1876,13 @@ static int volume_write(char *buf) * 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); + * 6 full speed 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. + * the tachometer while the fan controller ramps up + * the speed (which can take up to a few *minutes*). + * Speeds up fan to 100% duty-cycle, which is 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. @@ -1916,9 +1918,8 @@ static int volume_write(char *buf) * 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. + * FIRMWARE BUG: may go stale while the EC is switching to full speed + * mode. * * For firmware bugs, refer to: * http://thinkwiki.org/wiki/Embedded_Controller_Firmware#Firmware_Issues @@ -2283,9 +2284,6 @@ static int fan_read(char *p) len += sprintf(p + len, "status:\t\t%s\n", (status != 0) ? "enabled" : "disabled"); - /* No ThinkPad boots on disengaged mode, we can safely - * assume the tachometer is online if fan control status - * was unknown */ if ((rc = fan_get_speed(&speed)) < 0) return rc; |