Root/
1 | Kernel driver pc87360 |
2 | ===================== |
3 | |
4 | Supported chips: |
5 | * National Semiconductor PC87360, PC87363, PC87364, PC87365 and PC87366 |
6 | Prefixes: 'pc87360', 'pc87363', 'pc87364', 'pc87365', 'pc87366' |
7 | Addresses scanned: none, address read from Super I/O config space |
8 | Datasheets: No longer available |
9 | |
10 | Authors: Jean Delvare <khali@linux-fr.org> |
11 | |
12 | Thanks to Sandeep Mehta, Tonko de Rooy and Daniel Ceregatti for testing. |
13 | Thanks to Rudolf Marek for helping me investigate conversion issues. |
14 | |
15 | |
16 | Module Parameters |
17 | ----------------- |
18 | |
19 | * init int |
20 | Chip initialization level: |
21 | 0: None |
22 | *1: Forcibly enable internal voltage and temperature channels, except in9 |
23 | 2: Forcibly enable all voltage and temperature channels, except in9 |
24 | 3: Forcibly enable all voltage and temperature channels, including in9 |
25 | |
26 | Note that this parameter has no effect for the PC87360, PC87363 and PC87364 |
27 | chips. |
28 | |
29 | Also note that for the PC87366, initialization levels 2 and 3 don't enable |
30 | all temperature channels, because some of them share pins with each other, |
31 | so they can't be used at the same time. |
32 | |
33 | |
34 | Description |
35 | ----------- |
36 | |
37 | The National Semiconductor PC87360 Super I/O chip contains monitoring and |
38 | PWM control circuitry for two fans. The PC87363 chip is similar, and the |
39 | PC87364 chip has monitoring and PWM control for a third fan. |
40 | |
41 | The National Semiconductor PC87365 and PC87366 Super I/O chips are complete |
42 | hardware monitoring chipsets, not only controlling and monitoring three fans, |
43 | but also monitoring eleven voltage inputs and two (PC87365) or up to four |
44 | (PC87366) temperatures. |
45 | |
46 | Chip #vin #fan #pwm #temp devid |
47 | |
48 | PC87360 - 2 2 - 0xE1 |
49 | PC87363 - 2 2 - 0xE8 |
50 | PC87364 - 3 3 - 0xE4 |
51 | PC87365 11 3 3 2 0xE5 |
52 | PC87366 11 3 3 3-4 0xE9 |
53 | |
54 | The driver assumes that no more than one chip is present, and one of the |
55 | standard Super I/O addresses is used (0x2E/0x2F or 0x4E/0x4F) |
56 | |
57 | Fan Monitoring |
58 | -------------- |
59 | |
60 | Fan rotation speeds are reported in RPM (revolutions per minute). An alarm |
61 | is triggered if the rotation speed has dropped below a programmable limit. |
62 | A different alarm is triggered if the fan speed is too low to be measured. |
63 | |
64 | Fan readings are affected by a programmable clock divider, giving the |
65 | readings more range or accuracy. Usually, users have to learn how it works, |
66 | but this driver implements dynamic clock divider selection, so you don't |
67 | have to care no more. |
68 | |
69 | For reference, here are a few values about clock dividers: |
70 | |
71 | slowest accuracy highest |
72 | measurable around 3000 accurate |
73 | divider speed (RPM) RPM (RPM) speed (RPM) |
74 | 1 1882 18 6928 |
75 | 2 941 37 4898 |
76 | 4 470 74 3464 |
77 | 8 235 150 2449 |
78 | |
79 | For the curious, here is how the values above were computed: |
80 | * slowest measurable speed: clock/(255*divider) |
81 | * accuracy around 3000 RPM: 3000^2/clock |
82 | * highest accurate speed: sqrt(clock*100) |
83 | The clock speed for the PC87360 family is 480 kHz. I arbitrarily chose 100 |
84 | RPM as the lowest acceptable accuracy. |
85 | |
86 | As mentioned above, you don't have to care about this no more. |
87 | |
88 | Note that not all RPM values can be represented, even when the best clock |
89 | divider is selected. This is not only true for the measured speeds, but |
90 | also for the programmable low limits, so don't be surprised if you try to |
91 | set, say, fan1_min to 2900 and it finally reads 2909. |
92 | |
93 | |
94 | Fan Control |
95 | ----------- |
96 | |
97 | PWM (pulse width modulation) values range from 0 to 255, with 0 meaning |
98 | that the fan is stopped, and 255 meaning that the fan goes at full speed. |
99 | |
100 | Be extremely careful when changing PWM values. Low PWM values, even |
101 | non-zero, can stop the fan, which may cause irreversible damage to your |
102 | hardware if temperature increases too much. When changing PWM values, go |
103 | step by step and keep an eye on temperatures. |
104 | |
105 | One user reported problems with PWM. Changing PWM values would break fan |
106 | speed readings. No explanation nor fix could be found. |
107 | |
108 | |
109 | Temperature Monitoring |
110 | ---------------------- |
111 | |
112 | Temperatures are reported in degrees Celsius. Each temperature measured has |
113 | associated low, high and overtemperature limits, each of which triggers an |
114 | alarm when crossed. |
115 | |
116 | The first two temperature channels are external. The third one (PC87366 |
117 | only) is internal. |
118 | |
119 | The PC87366 has three additional temperature channels, based on |
120 | thermistors (as opposed to thermal diodes for the first three temperature |
121 | channels). For technical reasons, these channels are held by the VLM |
122 | (voltage level monitor) logical device, not the TMS (temperature |
123 | measurement) one. As a consequence, these temperatures are exported as |
124 | voltages, and converted into temperatures in user-space. |
125 | |
126 | Note that these three additional channels share their pins with the |
127 | external thermal diode channels, so you (physically) can't use them all at |
128 | the same time. Although it should be possible to mix the two sensor types, |
129 | the documents from National Semiconductor suggest that motherboard |
130 | manufacturers should choose one type and stick to it. So you will more |
131 | likely have either channels 1 to 3 (thermal diodes) or 3 to 6 (internal |
132 | thermal diode, and thermistors). |
133 | |
134 | |
135 | Voltage Monitoring |
136 | ------------------ |
137 | |
138 | Voltages are reported relatively to a reference voltage, either internal or |
139 | external. Some of them (in7:Vsb, in8:Vdd and in10:AVdd) are divided by two |
140 | internally, you will have to compensate in sensors.conf. Others (in0 to in6) |
141 | are likely to be divided externally. The meaning of each of these inputs as |
142 | well as the values of the resistors used for division is left to the |
143 | motherboard manufacturers, so you will have to document yourself and edit |
144 | sensors.conf accordingly. National Semiconductor has a document with |
145 | recommended resistor values for some voltages, but this still leaves much |
146 | room for per motherboard specificities, unfortunately. Even worse, |
147 | motherboard manufacturers don't seem to care about National Semiconductor's |
148 | recommendations. |
149 | |
150 | Each voltage measured has associated low and high limits, each of which |
151 | triggers an alarm when crossed. |
152 | |
153 | When available, VID inputs are used to provide the nominal CPU Core voltage. |
154 | The driver will default to VRM 9.0, but this can be changed from user-space. |
155 | The chipsets can handle two sets of VID inputs (on dual-CPU systems), but |
156 | the driver will only export one for now. This may change later if there is |
157 | a need. |
158 | |
159 | |
160 | General Remarks |
161 | --------------- |
162 | |
163 | If an alarm triggers, it will remain triggered until the hardware register |
164 | is read at least once. This means that the cause for the alarm may already |
165 | have disappeared! Note that all hardware registers are read whenever any |
166 | data is read (unless it is less than 2 seconds since the last update, in |
167 | which case cached values are returned instead). As a consequence, when |
168 | a once-only alarm triggers, it may take 2 seconds for it to show, and 2 |
169 | more seconds for it to disappear. |
170 | |
171 | Monitoring of in9 isn't enabled at lower init levels (<3) because that |
172 | channel measures the battery voltage (Vbat). It is a known fact that |
173 | repeatedly sampling the battery voltage reduces its lifetime. National |
174 | Semiconductor smartly designed their chipset so that in9 is sampled only |
175 | once every 1024 sampling cycles (that is every 34 minutes at the default |
176 | sampling rate), so the effect is attenuated, but still present. |
177 | |
178 | |
179 | Limitations |
180 | ----------- |
181 | |
182 | The datasheets suggests that some values (fan mins, fan dividers) |
183 | shouldn't be changed once the monitoring has started, but we ignore that |
184 | recommendation. We'll reconsider if it actually causes trouble. |
185 |
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