Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.
1 Kernel driver pc87427 2 ===================== 3 4 Supported chips: 5 * National Semiconductor PC87427 6 Prefix: 'pc87427' 7 Addresses scanned: none, address read from Super I/O config space 8 Datasheet: No longer available 9 10 Author: Jean Delvare <jdelvare@suse.de> 11 12 Thanks to Amir Habibi at Candelis for setting up a test system, and to 13 Michael Kress for testing several iterations of this driver. 14 15 16 Description 17 ----------- 18 19 The National Semiconductor Super I/O chip includes complete hardware 20 monitoring capabilities. It can monitor up to 18 voltages, 8 fans and 21 6 temperature sensors. Only the fans and temperatures are supported at 22 the moment, voltages aren't. 23 24 This chip also has fan controlling features (up to 4 PWM outputs), 25 which are partly supported by this driver. 26 27 The driver assumes that no more than one chip is present, which seems 28 reasonable. 29 30 31 Fan Monitoring 32 -------------- 33 34 Fan rotation speeds are reported as 14-bit values from a gated clock 35 signal. Speeds down to 83 RPM can be measured. 36 37 An alarm is triggered if the rotation speed drops below a programmable 38 limit. Another alarm is triggered if the speed is too low to be measured 39 (including stalled or missing fan). 40 41 42 Fan Speed Control 43 ----------------- 44 45 Fan speed can be controlled by PWM outputs. There are 4 possible modes: 46 always off, always on, manual and automatic. The latter isn't supported 47 by the driver: you can only return to that mode if it was the original 48 setting, and the configuration interface is missing. 49 50 51 Temperature Monitoring 52 ---------------------- 53 54 The PC87427 relies on external sensors (following the SensorPath 55 standard), so the resolution and range depend on the type of sensor 56 connected. The integer part can be 8-bit or 9-bit, and can be signed or 57 not. I couldn't find a way to figure out the external sensor data 58 temperature format, so user-space adjustment (typically by a factor 2) 59 may be required.