diff options
Diffstat (limited to 'Documentation/hwmon/it87')
| -rw-r--r-- | Documentation/hwmon/it87 | 53 |
1 files changed, 38 insertions, 15 deletions
diff --git a/Documentation/hwmon/it87 b/Documentation/hwmon/it87 index f9ba96c0ac4..8d08bf0d38e 100644 --- a/Documentation/hwmon/it87 +++ b/Documentation/hwmon/it87 @@ -5,31 +5,23 @@ Supported chips: * IT8705F Prefix: 'it87' Addresses scanned: from Super I/O config space (8 I/O ports) - Datasheet: Publicly available at the ITE website - http://www.ite.com.tw/product_info/file/pc/IT8705F_V.0.4.1.pdf + Datasheet: Once publicly available at the ITE website, but no longer * IT8712F Prefix: 'it8712' Addresses scanned: from Super I/O config space (8 I/O ports) - Datasheet: Publicly available at the ITE website - http://www.ite.com.tw/product_info/file/pc/IT8712F_V0.9.1.pdf - http://www.ite.com.tw/product_info/file/pc/Errata%20V0.1%20for%20IT8712F%20V0.9.1.pdf - http://www.ite.com.tw/product_info/file/pc/IT8712F_V0.9.3.pdf + Datasheet: Once publicly available at the ITE website, but no longer * IT8716F/IT8726F Prefix: 'it8716' Addresses scanned: from Super I/O config space (8 I/O ports) - Datasheet: Publicly available at the ITE website - http://www.ite.com.tw/product_info/file/pc/IT8716F_V0.3.ZIP - http://www.ite.com.tw/product_info/file/pc/IT8726F_V0.3.pdf + Datasheet: Once publicly available at the ITE website, but no longer * IT8718F Prefix: 'it8718' Addresses scanned: from Super I/O config space (8 I/O ports) - Datasheet: Publicly available at the ITE website - http://www.ite.com.tw/product_info/file/pc/IT8718F_V0.2.zip - http://www.ite.com.tw/product_info/file/pc/IT8718F_V0%203_(for%20C%20version).zip + Datasheet: Once publicly available at the ITE website, but no longer * IT8720F Prefix: 'it8720' Addresses scanned: from Super I/O config space (8 I/O ports) - Datasheet: Not yet publicly available. + Datasheet: Not publicly available * SiS950 [clone of IT8705F] Prefix: 'it87' Addresses scanned: from Super I/O config space (8 I/O ports) @@ -136,6 +128,10 @@ registers are read whenever any data is read (unless it is less than 1.5 seconds since the last update). This means that you can easily miss once-only alarms. +Out-of-limit readings can also result in beeping, if the chip is properly +wired and configured. Beeping can be enabled or disabled per sensor type +(temperatures, voltages and fans.) + The IT87xx only updates its values each 1.5 seconds; reading it more often will do no harm, but will return 'old' values. @@ -150,11 +146,38 @@ Fan speed control ----------------- The fan speed control features are limited to manual PWM mode. Automatic -"Smart Guardian" mode control handling is not implemented. However -if you want to go for "manual mode" just write 1 to pwmN_enable. +"Smart Guardian" mode control handling is only implemented for older chips +(see below.) However if you want to go for "manual mode" just write 1 to +pwmN_enable. If you are only able to control the fan speed with very small PWM values, try lowering the PWM base frequency (pwm1_freq). Depending on the fan, it may give you a somewhat greater control range. The same frequency is used to drive all fan outputs, which is why pwm2_freq and pwm3_freq are read-only. + + +Automatic fan speed control (old interface) +------------------------------------------- + +The driver supports the old interface to automatic fan speed control +which is implemented by IT8705F chips up to revision F and IT8712F +chips up to revision G. + +This interface implements 4 temperature vs. PWM output trip points. +The PWM output of trip point 4 is always the maximum value (fan running +at full speed) while the PWM output of the other 3 trip points can be +freely chosen. The temperature of all 4 trip points can be freely chosen. +Additionally, trip point 1 has an hysteresis temperature attached, to +prevent fast switching between fan on and off. + +The chip automatically computes the PWM output value based on the input +temperature, based on this simple rule: if the temperature value is +between trip point N and trip point N+1 then the PWM output value is +the one of trip point N. The automatic control mode is less flexible +than the manual control mode, but it reacts faster, is more robust and +doesn't use CPU cycles. + +Trip points must be set properly before switching to automatic fan speed +control mode. The driver will perform basic integrity checks before +actually switching to automatic control mode. |