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Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.

1	Kernel driver pc87427
2	=====================
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
10	Author: Jean Delvare <jdelvare@suse.de>
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.
16	Description
17	-----------
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.
24	This chip also has fan controlling features (up to 4 PWM outputs),
25	which are partly supported by this driver.
27	The driver assumes that no more than one chip is present, which seems
28	reasonable.
31	Fan Monitoring
32	--------------
34	Fan rotation speeds are reported as 14-bit values from a gated clock
35	signal. Speeds down to 83 RPM can be measured.
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).
42	Fan Speed Control
43	-----------------
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.
51	Temperature Monitoring
52	----------------------
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.
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