Root/
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 <khali@linux-fr.org> |
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. |
60 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
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