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1Sensors FAQ for lm_sensors version 2
2------------------------------------
3
4    Copyright (c) 1998, 1999, 2000, 2001  Frodo Looijaard <frodol@dds.nl>,
5    Philip Edelbrock <phil@netroedge.com>, and Mark Studebaker <mdsxyz123@yahoo.com>
6
7------------------------------------------------------------------------------------
8
9CONTENTS
10
111. PC and Sensor Overview
121.1 What sensors are available on my PC?
131.2 What can a sensor chip like the "LM78" do?
141.3 Where do I find out more about any of these LMxx chips?
15
162. Sensor and Bus Basics
172.1 How are these sensors read?
182.2 What is the SMBus? And the I2C bus?
192.3 I don't have an ISA bus!
202.4 What sensors do processors have?
212.5 How often are the sensor values updated?
222.6 How are alarms triggered?
23
243 Installation and Management
253.1 Why so many modules, and how do I cope with them?
263.2 How do I know which chips I own?
27  3.2A What chips are on motherboard XYZ?
28  3.2B Do you support motherboard XYZ?
29  3.2C Do you support chip XYZ?
30  3.2D Anybody working on a driver for chip XYZ?
313.3 Which modules should I insert?
323.4 Do I need the configuration file?
33  3.4A The labels for the voltage and temperature readings in 'sensors' are incorrect!
34  3.4B The min and max for the readings in 'sensors' are incorrect!
35  3.4C The min and max settings in /etc/sensors.conf didn't take effect!
36  3.4D One sensor isn't hooked up on my board!
373.5 What about the 'No such file or directory' warnings when I compile it?
383.6 I get all kind of weird compilation errors?
393.7 It still does not compile or patch
40
414 Problems
424.1 Why do my fans report exactly half/double their values by your code
43compared to the BIOS?
444.2 Why do my two LM75's report "-48 degrees"?
454.3 Why do I have two Vcore readings, I have only one processor!
464.4 How do those ALARMS work? The current value is within range but there
47is still an ALARM warning!
484.5 My voltage readings seem to drift a bit. Is something wrong with my power
49supply?
504.6 Some measurements are way out of range. What happened?
514.7 What are VID lines?
524.8 I read sensor values several times a second, but they are only
53updated only each second or so. Why?
544.9 It sometimes seems to take almost a second before I see the
55sensor reading results. Why?
564.10 Can I be alerted when an ALARM occurs?
574.11 SMBus transactions on my PIIX4 simply don't work (timeouts happen).  Why?
584.12 My BIOS reports a much higher CPU temperature than your modules!
594.13 I try to read the raw /proc files, but the values are strange?!?
604.14 How do I set new limits?
61  4.14A  I set new limits and it didn't work?
624.15 Some sensors are doubly detected?
634.16 I ran sensors-detect, but now I get very strange readings?!?
644.17 Bad readings from the particular chips
65  4.17A Bad readings from the AS99127F!
66  4.17B Bad readings from the VIA 686A!
67  4.17C Bad readings from the MTP008!
684.18 How do I configure two chips (LM87) differently?
694.19 Dmesg says Upgrade BIOS! I don't want to!
704.20 Sensors says 'Can't access /proc file'
714.21 Sensors says 'No sensors found!'
724.22 Sensors output is not correct!
734.23 What is at I2C address XXX?
74  4.23A What is at I2C address 0x69?
75  4.23B What is at I2C addresses 0x50 - 0x57?
76  4.23C What is at I2C addresses 0x30 - 0x37?
774.24 Sensors-detect doesn't work at all
78  4.24A Sensors-detect says "Couldn't open /proc/bus/i2c?!?"
79  4.24B Sensors-detect says "Can't open /dev/i2c[-/]0"
80  4.24C Sensors-detect doesn't find any sensors
81
825 How to Ask for Help 
835.1 What to do if a module won't insert?
845.2 What to do if it inserts, but nothing happens?
855.3 What to do if I read only bogus information?
865.4 What to do if you have other problems?
875.5 What if it just works like a charm?
88
896 Version 1 specific questions
906.1 My manufacturer swears that my mainboard has an SMBus, but your code
91reports that it can't find it.  What's wrong?
926.2 The modules won't load, saying 'SMBus not detected'.
936.3 I try to read /proc/sensors, and I get a "No sensor data yet (try again in
94a few moments)" message. Why?
95
96-------------------------------------------------------------
97
98
991. PC and Sensor Overview
100--------------------------------------
101
1021.1 What sensors are available on my PC?
103
104    Most PC's built since late 1997 now come with a
105hardware health monitoring chip. This chip may be accessed via the
106ISA bus or the SMBus, depending on the motherboard.
107    Some motherboard chipsets, notably the Via 686 and the SiS 5595,
108contain hardware monitor functions.
109    This FAQ frequently refers to the "LM78". This chip has been
110obsoleted by National Semiconductor. Most motherboards today contain
111a chip with similar functions.
112
113   
1141.2 What can a sensor chip like the "LM78" do?
115
116    The LM78 is a chip made by National Semiconductor which can monitor 7
117voltages (5 positive, 2 negative) from 0 to 4.08V.  The inputs are usually in
118series with voltage dividers which lower the +/- 12V and +/- 5V supplies to
119measurable range.  Therefore, the readings for such inputs need to be
120re-scaled appropriately by software.
121    The LM78 also has 3 fan speed monitoring inputs, an internal
122temperature sensor, a chassis intrusion sensor, and a couple maskable interrupt
123inputs.  The LM78 can also relay the processor's (P6 or Pent II) VID lines
124which are hardwired and used to indicate to the power regulator (usually on
125the mainboard close to the processor socket/slot) what voltage to supply to
126the processor.
127    The LM78 can be interfaced to a system via the ISA bus and/or the
128SMBus.
129    Most other sensor chips have comparable functionality. Each supported
130chip is documented in the doc/chips directory.
131
132   
1331.3 Where do I find out more about any of these chips?
134
135    Most semiconductor companies have comprehensive documentation,
136including complete datasheets, on their websites. Analog Devices,
137Dallas Semiconductor, Maxim, and National Semiconductor have the widest selection
138of sensor chips. Their websites are:
139        http://www.analog.com
140        http://www.dalsemi.com
141        http://www.maxim-ic.com
142        http://www.national.com
143    Please see the file http://www2.lm-sensors.nu/~lm78/useful_addresses.html
144for links to other companies' websites.
145
146
147
1482 Sensor and Bus Basics
149-----------------------------
150
1512.1 How are these sensors read?
152
153    Sensor chips reside on either the ISA bus, the SMBus, or both.
154See the file doc/chips/SUMMARY in our package for a list.
155    To communicate with chips on the ISA bus, the software uses
156simple I/O reads and writes.
157    To communicate with chips on the SMBus, the software must
158use an SMBus interface device, explained below.
159   
160
1612.2 What is the SMBus? And the I2C bus?
162
163    The SMBus is the "System Management Bus".  More specifically, it is a
1642-wire, low-speed serial communication bus used for basic health monitoring
165and hardware management. It is a specific implementation of the more
166general I2C (pronunciation: I-squared-C) bus. In fact, both I2C devices
167and SMBus devices may be connected to the same (I2C) bus.
168    The SMBus (or I2C bus) starts at the host controller, used for
169starting transactions on the SMBus.  From the host interface, the
170devices communicated with are the 'slave' devices.  Each slave device has a
171unique 7-bit address in which the host must refer to it with.
172    For each supported SMBus host, there is a separate kernel module
173which implements the communication protocol with the host. Some SMBus hosts
174really operate on the SMBus level; these hosts can not cope with pure I2C
175devices. Other hosts are in fact I2C hosts: in this case, we implement
176the SMBus protocol in terms of I2C operations. But these hosts can also
177talk to pure I2C devices.
178   
179
1802.3 I don't have an ISA bus!
181
182    We promise, you do, even if you don't have any old ISA slots.
183The "ISA Bus" exists in your computer even if you don't have ISA slots;
184it is simply a memory-mapped area, 64KB in size (0x0000 - 0xFFFF)
185where many "legacy" functions, such as keyboard and interrupt controllers,
186are found. See the file /proc/ioports for a list of devices living on
187the "ISA Bus" in your system.
188
189
1902.4 What sensors do processors have?
191
192    Most new processors contain a thermal diode on the die itself.
193The electical properties of all diodes and transistors vary
194slightly with temperature. The thermal diode is exceptionally accurate
195because it is directly on the die. Newer temperature sensor chips,
196like the Analog Devices ADM1021 and clones, and the Winbond chips,
197have circuitry for measuring the the electrical properties of
198an external diode and converting this data to a temperature.
199Any sensor chip listed in doc/chips/SUMMARY in our package which
200has support for more than one temperature supports external temperature sensing.
201    Older motherboards and processors without this feature generally use
202an LM75 placed close to the processor. This is much less accurate.
203    The Pentium 2 'boxed' processor usually has an LM75 very close to the
204base of the box. It can be read through the SMBus to report the approximate
205temperature of the processor.  The processor also contains an internal
206temperature sensor (of low accuracy) used as a fail-safe to disable the
207processor in case it gets much too hot (usually around 130 degrees C).  And,
208the Pentium 2 also has a hard-wired signal (VID lines) on it's SEC (single
209edge connector) which indicates what power supply is required to operate the
210processor.
211    The P6 (Pentium-Pro) may have an LM75 in or just under the socket. 
212P6's also have VID lines.
213    Pentiums and Pentium w/ MMX do not have VID lines, and sometimes have
214LM75's under the sockets (depends on the mainboard, and how 'modern' the
215mainboard is).
216    The P2 Xeon was the first Intel processor to include the SMBus
217interface on the P2 Xeon SEC.
218   
219
2202.5 How often are the sensor values updated?
221
222    The LM78, and most other sensor chips like it, reads its sensors one
223by one. A complete scanning sweep will take about 1.5 seconds. The LM78 stops
224readings sensors if you try to access it, so if you access it very often
225(by reading sensor values; writing new limits is safe) it will not find the
226time to update its sensor values at all! Fortunately, the kernel module takes
227care not to do this, and only reads new values each 1.5 seconds. If you
228read the values again, you will get the 'old' values again.
229
230
2312.6 How are alarms triggered?
232
233    It is possible to monitor each sensor and let an alarm go off if
234it crosses some pre-determined limits.  There are two sorts of interrupts
235which can be generated by sensor chips if this happens (it depends a bit on
236the actual chip if both are supported; the LM80, for example, has only
237IRQ interrupts): IRQ interrupts and SMI interrupts.  IRQ stands for
238Interrupt Request and are the interrupt lines you can find in /proc/interrupts.
239SMI stands for System Management Interrupt, and is a special interrupt which
240puts the processor in a secure environment independent of any other things
241running.  SMI is currently not supported by the Linux kernel.  IRQs are
242supported, of course.
243    Even if no interrupt is generated, some bits in a status register
244will be set until the register is read the next time. If the alarm condition
245persists after that, the bits will be set on the next scanning sweep, etc.
246    At this moment, interrupts are not supported.
247
248
249
2503 Installation and management
251-----------------------------
252
2533.1 Why so many modules, and how do I cope with them?
254
255    We tried to make this package as modular as possible. This makes it
256easy to add new drivers, and unused drivers will take no precious kernel
257space. On the other hand, it can be a bit confusing at first.
258    Here are two simple guidelines:
259        * Run 'sensors-detect' and do what it tells you.
260        * Always use 'modprobe', not 'insmod'.
261    Further information is in doc/modules.
262
263
2643.2 How do I know which chips I own?
265
266    We have an excellent program that scans all your hardware.
267It is called 'sensors-detect' and is installed in /usr/local/sbin
268by 'make install'. Just execute this script, and it will tell you.
269    Chip detection in the drivers is fairly good. That means that it is
270usually harmless to insert more chip drivers than you need. However, this
271can still lead to problems, so we do not recommend it.
272    If sensors-detect didn't find any sensors, either you don't have
273any, or the ones you have, we don't support. Look at your motherboard
274for candidates, then go to section 5.
275
276
2773.2A What chips are on motherboard XYZ?
278
279    We have no idea. Here is what you should do:
280        1) Run sensors-detect.
281    If that doesn't work:
282        2) Look at your motherboard.
283        3) Check the manufacturer's website.
284        4) Check the Motherboard Monitor website
285           (see useful_addresses.html) for a good cross-reference.
286
287
2883.2B Do you support motherboard XYZ?
289
290    See 3.2A.
291
292
2933.2C Do you support chip XYZ?
294
295    This we have good answers for.
296        Sorted by Manufacturer:   README
297        Sorted by Manufacturer:   http://www2.lm-sensors.nu/~lm78/supported.html
298        Sorted by Sensor Driver:  doc/chips/SUMMARY
299        Newest Driver Status:     http://www2.lm-sensors.nu/~lm78/newdrivers.html
300       
301
3023.2D Anybody working on a driver for chip XYZ?
303
304        Newest Driver Status:     http://www2.lm-sensors.nu/~lm78/newdrivers.html
305
306
3073.3 Which modules should I insert?
308
309    'sensors-detect' will tell you. Take the 'modprobe' lines it
310recommends and paste them into the appropriate /etc/rc.d/xxxx file
311to be executed at startup.
312    You need one module for each sensor chip and bus adapter you own;
313if there are sensor chips on the ISA bus, you also need i2c-isa.o.
314for each type of chip you own. That's all. On my computer, I could use the
315following lines:
316        modprobe i2c-isa
317        modprobe i2c-piix4
318        modprobe lm78
319        modprobe lm75
320        modprobe i2c-dev
321        sensors -s
322
323
3243.4 Do I need the sensors.conf configuration file?
325
326    Yes, for any applications that use libsensors, including the
327'sensors' application included in our package.
328It tells libsensors how to translate the values the chip
329measures to real-world values. This is especially important for voltage
330inputs. The default configuration file should usually do the trick.
331It is automatically installed as /etc/sensors.conf, but it will not
332overwrite any existing file with that name.
333
334
3353.4A The labels for the voltage and temperature readings in 'sensors' are incorrect!
336
337    Every motherboard is different. You can customize the labels
338in the file /etc/sensors.conf. That's why it exists!
339The default labelling (in lib/chips.c and /etc/sensors.conf) is just
340a template.
341
342
3433.4B The min and max for the readings in 'sensors' are incorrect!
344
345    You can customize them in the file /etc/sensors.conf. See above.
346
347
3483.4C The min and max settings in /etc/sensors.conf didn't take effect!
349
350    You forgot to run 'sensors -s'. See above.
351
352
3533.4D One sensor isn't hooked up on my board!
354
355    Use an 'ignore' line in /etc/sensors.conf so it isn't
356displayed in 'sensors'.
357
358
3593.5 What about the 'No such file or directory' warnings when I compile it?
360
361    Don't worry about them. The dependency files (which tell which
362files should be recompiled when certain files change) are created
363dynamically. They are not distributed with the package. The `make' program
364notices they are not there, and warns about that - and the first thing
365it will do is generate them. So all is well.
366
367
3683.6 I get all kinds of weird compilation errors?
369
370    Check that the correct i2c header files are used. Depending on
371how you installed, they should be under either /usr/local/include or
372/usr/src/linux*/include. Try to edit the Makefile for the other setting.
373
374
3753.7 It still does not compile or patch!
376
377    Have you installed the matching version of the i2c package? Remember,
378compilation is not enough, you also need to install it for the header
379files to be found!
380    If you want to patch the kernel, you will have to apply the i2c
381patches first!
382
383
384
3854 Problems
386----------
387
3884.1 Why do my fans report exactly half/double their values by your code
389compared to the BIOS?
390
391    The problem with much of the sensor data is that it is impossible to
392properly interpret some of the readings without knowing what the hardware
393configuration is.  Some fans report one 'tick' each rotation, some report
394two 'ticks' each rotation. It is easy to resolve this through the
395configuration file:
396    chip lm78-*               # Or whatever chip this relates to
397    compute fan1 2*@,@/2      # Copy for each fan present
398
399
4004.2 Why do my two LM75's report "-48 degrees"?
401
402    For starters, those aren't LM75's.  Your mainboard actually has the
403Winbond W83781D which emulates two LM75's, but many systems which use the
404Winbond chip (such as the Asus P2B) don't have the thermo-resisters connected
405to the chip resulting in these strange -48 degree readings.
406    If you have an Asus P2B and want more information on adding thermal
407sensing capability, check out:
408http://ultimatepc.fsn.net/techinfo/p2bthermistor/p2bthermistor.htm
409    In upcoming versions, you will be able to disable non-interesting
410readings.
411
412
4134.3 Why do I have two Vcore readings, I have only one processor!
414
415    The LM78 has seven voltage sensors. The default way of
416connecting them is used in the configuration file. This includes a VCore2,
417even if you do not have one. You can easily edit the configuration file
418to give it another name, or (in upcoming versions) to make this reading
419disappear.
420    Note that Vcore2 is often the same as Vcore on motherboards which
421only support one processor. Another possibility is that Vcore2 is not
422connected at all and will not have a valid reading at all.
423A third possibility, is that Vcore2 monitors something
424else, so you should not be too surprised if the values are completely
425different.
426
427
4284.4 How do those ALARMS work? The current value is within range but there
429is still an ALARM warning!
430
431    The ALARM indications in 'sensors' are those reported by the
432sensor chip itself. They are NOT calculated by 'sensors'.
433    An ALARM will go off when a minimum or maximum limit is crossed.
434The ALARM is then latched - that is, it will stay there until the
435chip's registers are next accessed - which will be the next time
436you read these values, but not within (usually) 1.5 seconds since the last
437update.
438    Reading the registers clears the ALARMS, unless the current
439value is still out of range.
440    The purpose of this scheme is to tell you if there has been
441a problem and report it to the user. Voltage or temperature spikes
442get detected without having to read the sensor chip hundreds of times
443a second. The implemetation details depend a bit on the kind of chip.
444See the specific chip documentation in doc/chips and the
445chip datasheet for more information.
446
447
4484.5 My voltage readings seem to drift a bit. Is something wrong with my power
449supply?
450
451    No, probably not. If your motherboard heats up a bit, the sensed
452voltages will drift a bit. If your power supply is loaded (because a disk
453gets going, for example), the voltages may get a bit lower. As long as they
454stay within a sensible range (say 10% of the expected value), there is no
455reason to worry.
456
457
4584.6 Some measurements are way out of range. What happened?
459
460    Each module tries to set limits to sensible values on initialization,
461but a module does not know how a chip is actually connected. This is
462described in the configuration file, which is not read by kernel modules.
463So limits can be strange, if the chip is connected in a non-standard way.
464    Readings can also be strange; there are several reasons for this.
465Temperature sensors, for example, can simply not be present, even though
466the chip supports them. Also, it can be that the input is used in a
467non-standard way. You can use the configuration file to describe how this
468measurement should be interpreted; see the comments the example file for
469more information.
470
471
4724.7 What are VID lines?
473
474    These describe the voltage your processors use. This is supported
475for most processors, however they are not always
476correctly connected to the sensor chip, so the readings may be out of
477range. A value of +3.5 V is especially suspect.
478
479
4804.8 I read sensor values several times a second, but they are only
481updated only each second or so. Why?
482
483    If we would read the registers more often, it would not find the
484time to update them. So we only update our readings once each 1.5 seconds
485(the actual delay is chip-specific; for some chips, it may not be needed
486at all).
487
488
4894.9 It sometimes seems to take almost a second before I see the
490sensor reading results. Why?
491
492    ISA bus access is fast, but SMBus access is really slow. If you have
493a lot of sensors, it just takes a lot of time to access them. Fortunately,
494this has almost no impact on the system as a whole, as another job can run
495while we are waiting for the transaction to finish.
496
497
4984.10 Can I be alerted when an ALARM occurs?
499
500    No, you can't; and it may well be never supported.
501    Almost no mainboard we have encountered have actually connected the
502IRQ-out pin of sensor chips. That means that we could enable IRQ reporting, but
503nothing would happen. Also, even if a motherboard has it connected, it is
504unclear what interrupt number would be triggered. And IRQ lines are a scarce
505facility, which means that almost nobody would be able to use it anyway.
506    The SMI interrupt is only available on a few types of chips. It is
507really a very obscure way to handle interrupts, and supporting it under Linux
508might be quite hard to do.
509    Your best bet would be to poll the alarm file with a user-land daemon
510which alerts you if an alarm is raised. I am not aware of any program which
511does the job, though you might want to examine one of the graphical monitor
512programs under X, see doc/useful_addresses.html for addresses.
513
514
5154.11 SMBus transactions on my PIIX4 simply don't work (timeouts happen).  Why?
516
517    Some chips which mainboard makers connect to the SMBus are not SMBus
518devices.  An example is the 91xx clock generator chips.  When read, these
519devices can lock up the SMBus until the next hard reboot.  This is because
520they have a similar serial interface (like the I2C), but don't conform to
521Intel's SMBus standard.
522    Why did they connect these devices to the SMBus if they aren't
523compatible?  Good question! :')  Actually, these devices may support being
524written to, but lock things up when they are read.
525
526
5274.12 My BIOS reports a much higher CPU temperature than your modules!
528
529    We display the actual temperature of the sensor. This may not be the
530temperature you are interested in, though.  If a sensor should measure
531the CPU temperature, it must be in thermal contact with it.  In practice,
532it is just somewhere near it. Your BIOS may correct for this (by adding,
533for example, thirty degrees to the measured temperature).  The correction
534factor is regrettably different for each mainboard, so we can not do this
535in the module itself. You can do it through the configuration file, though:
536 
537    chip lm75-*-49                     # Or whatever chip this relates to
538    label temp "Processor"
539    compute temp @*1.2+13,(@-13)/1.2   # Or whatever formula
540
541
5424.13 I try to read the raw /proc files, but the values are strange?!?
543
544    Remember, these values do not take the configuration file
545'compute' lines in account. This is especially obvious for voltage readings
546(usually called in? or vin?). Use a program linked to libsensors (like
547the provided 'sensors' program) instead.
548
549
5504.14 How do I set new limits?
551
552    Change the limit values in /etc/sensors.conf and then run
553'sensors -s'.
554
555
5564.14A  I set new limits and it didn't work?
557
558    You forgot to run 'sensors -s'. Put it in a /etc/rc.d/... file
559after the modprobe lines to run at startup.
560
561
5624.15 Some sensors are doubly detected?
563
564    Yes, this is still a problem. It is partially solved by alias detection
565and confidence values in sensors-detect, but it is really tough.
566    Double detections can be caused by two things:
567sensors can be detected to both the ISA and the SMBus (and if you have
568loaded the approprate adapter drivers, it will be detected on both), and
569some chips simulate other chips (the Winbond W83781D simulates LM75 chips
570on the SMBus, for example). Remove the offending adapter or chip driver, or
571run sensors-detect and add the "ignore=" modprobe parameters it suggests.
572
573
5744.16 I ran sensors-detect, but now I get very strange readings?!?
575
576    Your SMBus (PIIX4?) is probably crashed or hung. There are some mainboards
577which connect a clock chip to the SMBus. Unfortunately, this clock chip
578hangs the PIIX4 if it is read (it is an I2C device, but not SMBus compatible).
579We have found no way of solving this, except for rebooting your computer.
580Next time when you run sensors-detect, you may want to exclude addresses
5810x69 and/or 0x6a, by entering 's' when you are asked whether you want to
582scan the PIIX4.
583
584
5854.17 Bad readings from particular chips
586
587    See below for some particularly troublesome chips.
588Also be sure and check doc/chips/xxxxx for the particular driver.
589
590
5914.17A Bad readings from the AS99127F!
592
593    The Asus AS99127F is a modified version of the Winbond W83781D.
594Asus will not release a datasheet. The driver was developed by tedious
595experimentation. We've done the best we can. If you want to make adjustments
596to the readings please edit /etc/sensors.conf. Please don't ask us to
597fix the driver. Ask Asus to release a datasheet.
598
599
6004.17B Bad readings from the VIA 686A!
601
602    The Via 686A datasheet is incomplete.
603Via will not release details. The driver was developed by tedious
604experimentation. We've done the best we can. If you want to make adjustments
605to the readings please edit /etc/sensors.conf. Please don't ask us to
606fix the driver. Ask Via to release a better datasheet.
607
608
6094.17C Bad readings from the MTP008!
610
611    The MTP008 has programmable temperature sensor types.
612If your sensor type does not match the default, you will have to change it.
613See doc/chips/mtp008 for details.
614
615
6164.18 How do I configure two chips (LM87) differently?
617
618    There is a SuperMicro board with two LM87's on it that are
619not hooked up in the same way, so they need different defaults.
620For example, both CPU temperatures go to one LM87.
621
622    Make two different sections in /etc/sensors.conf as follows:
623        chip "lm87-i2c-*-2c"
624                put configuration for the chip at 0x2c here
625        chip "lm87-i2c-*-2d"
626                put configuration for the chip at 0x2d here
627
628
6294.19 Dmesg says Upgrade BIOS! I don't want to!
630
631    If the problem is a PCI device is not present in 'lspci', the solution
632is complex. For the ALI M7101 device, there is a solution which uses the
6332.4 kernel's 'hotplug' facility. See prog/hotplug in our package.
634For other PCI devices, you can try to modify the m7101 solution in prog/hotplug.
635    If the problem is a PCI device whose base address is not set,
636you may be able to set the address with a force parameter. For the via686a
637driver, use the command line 'modprobe via686a force=9191,0xADDRESS' where
638ADDRESS is the I/O address (cat /proc/ioports to verify you don't have
639a conflict). Other drivers (for example sis5595) generally do not
640support the force parameter. Sorry. You can send us your request.
641
642
6434.20 Sensors says 'Can't access /proc file'
644
645    Did you 'modprobe sensors'? Check 'lsmod'.
646
647
6484.21 Sensors says 'No sensors found!'
649
650    Did sensors-detect find sensors? (If not see 4.23C)
651    Did you do what sensors-detect said?
652    Did you 'modprobe' your sensor modules?
653    Did you 'modprobe' your I2C adapter modules?
654    Did you 'modprobe i2c-isa' if you have ISA sensor chips?
655    Check 'lsmod'.
656
657
658
6594.22 Sensors output is not correct!
660
661    What specifically is the trouble?
662        Labels: See 3.4A above.
663        Min/max readings: See 3.4B&C above.
664        AS99127F: See 4.17 above
665        Via 686A: See 4.18 above
666        No output for a particular sensors chip: See 5.2 below
667        No output at all: See 4.21, 4.22 above; 5.2 below
668        Completely bad output for a particular sensor chip: See 5.3 below
669        One particular sensor readings:
670            Maybe it isn't hooked up;
671                tell 'sensors' to ignore it. See 3.4D above.
672            Maybe it is hooked up differently on your motherboard;
673                adjust sensors.conf calculation.
674
675
6764.23 What is at I2C address XXX?
677
678    In general, we don't know. Start by running sensors-detect.
679If it doesn't recognize it, try running i2cdump. A partial list
680of manufacturers' IDs are at the bottom of doc/chips/SUMMARY.
681
682
6834.23A What is at I2C address 0x69?
684
685    A clock chip. Often, accessing these clock chips in the wrong
686way will instantly crash your computer. Sensors-detect carefully
687avoids these chips. If you really really want to play with your clock
688chip you can look at kernel/chips/icspll.c in our package. But we
689do not recommend it. You have been warned.
690
691
6924.23B What is at I2C addresses 0x50 - 0x57?
693
694    EEPROMs on your SDRAM DIMMs. Load the eeprom module to
695look at some basic data in 'sensors' or use the program
696prog/eeprom/decode-dimms.pl to get more information than you ever wanted.
697
698
6994.23C What is at I2C addresses 0x30 - 0x37?
700
701    These are often 'shadows' of you EEPROMs on your SDRAM DIMMs
702at addresses 0x50 - 0x57. They aren't really there. If you try and
703do a 'i2cdump' on them you won't get anything. This is probably
704caused by some timing problem on your motherboard or on the DIMMs.
705We don't know the exact cause.
706
707
7084.24 Sensors-detect doesn't work at all
709
710    It could be many things. What was the problem? See below
711    in questions 4.24 A-C.
712
713
7144.24A Sensors-detect says "Couldn't open /proc/bus/i2c?!?"
715
716    You don't have i2c support in your kernel, or the i2c-core module
717was not loaded and you did not run sensors-detect as root.
718
719
7204.24B Sensors-detect says "Can't open /dev/i2c[-/]0"
721
722    Your /dev/i2c-0, /dev/i2c0, or /dev/i2c/0 files do not exist
723or you did not run sensors-detect as root.
724Run the script prog/mkdev/mkdev.sh to create the /dev/i2c-x files.
725Run devfs in the kernel to get the /dev/i2c/x files.
726
727
7284.24C Sensors-detect doesn't find any sensors!
729
730    Either
731        1) The board doesn't have any sensors.
732        2) We don't support the sensors on the board.
733        3) The sensors it has are on an I2C bus connected to an
734           I2C bus adapter that we don't support.
735    But in any case you should figure out what is on the board:
736        1) Look at your motherboard.
737        2) Check the manufacturer's website.
738        3) Check the Motherboard Monitor website
739           (see useful_addresses.html) for a good cross-reference.
740
741
7425 How to ask for help
743---------------------
744
745    We are always willing to answer questions if things don't work out.
746Please mail sensors@stimpy.netroedge.com, and not the individual authors,
747unless you have something private to say.
748    Instead of using email, you can also use the web-based support
749area, at http://www.netroedge.com/~lm78/support.html. You will be helped
750just as fast, and others may profit from the answer too. You will be
751noticed automatically when your question has been answered.
752
753    Here's what you should send us:
754
755    - The dmesg or syslog output if applicable
756    - The output of (as root) 'prog/detect/sensors-detect'
757    - The output of 'lsmod'
758    - If a PCI chip problem:
759        * The output of 'lspci' or 'cat /proc/pci'
760    - If a I2C sensor chip problem:
761        * The output of (as root) 'prog/detect/i2cdetect X'
762              X = the bus number
763              (run 'i2cdetect' with no arguments to list the busses)
764        * The output of (as root) 'prog/dump/i2cdump X 0xXX'
765              XX = the address of each chip you see in the output
766              of i2cdetect. (run once for each chip)
767    - If a ISA sensor chip problem:
768        * The output of (as root) 'prog/dump/isadump 0x295 0x296'
769    - Part numbers of chips on your motherboard you think are
770          the sensor chips (look at your motherboard)
771    - Motherboard type
772    - Sensors version
773    - Kernel version
774
775
7765.1 What to do if a module won't insert?
777
778    Did you use 'modprobe' instead of 'insmod'??? Don't use insmod.
779    Were there unresolved symbols? Did you run 'depmod -a'? Run
780'depmod -a -e' to see where the symbol problem is.
781    Always inspect the output of 'dmesg'. That's where the error
782messages come out. Don't rely on the generic message from 'modprobe'.
783If you still can't figure it out, send us the information
784listed above.
785
786
7875.2 What to do if it inserts, but nothing happens?
788
789    For an ISA sensor chip, did you also 'modprobe i2c-isa'? It must be inserted.
790    For an I2C sensor chip, did you also 'modprobe i2c-xxx' where xxx is your
791I2C bus adapter? It must be inserted.
792    Always inspect the output of 'dmesg'. That's where the error
793messages come out. If you still can't figure it out, send us the information
794listed above.
795
796
7975.3 What to do if I read only bogus information?
798
799    It may be that this was a mis-detection: the chip may not be
800present. If you are convinced there is something wrong, verify that you
801indeed have the devices on your motherboard that you think you do.
802Look at the motherboard and make sure. If you are still stuck,
803please send us the usual information (see section 5).
804
805
8065.4 What to do if you have other problems?
807
808    Again, send the output listed above.
809
810
8115.5 What if it just works like a charm?
812
813    Drop us a mail if you feel like it, mentioning the mainboard and
814detected chip type. That way, we have some positive feedback, too!
815
816
817
8186 Version 1 specific questions
819------------------------------
820
821Note: Version 1 is very very old and is not recommended.
822
8236.1 My manufacturer swears that my mainboard has an SMBus, but your code
824reports that it can't find it.  What's wrong?
825
826    Currently, our code only assumes that an SMBus exists if it originates
827from the Intel PIIX4 (82371AB).  If your computer doesn't have one, or if your
828SMBus originates from a different SMBus 'host', then you are out of luck. :'(
829Our experience is, though, that most machines have a PIIX4, and that it is
830where the SMBus is hosted.
831
832Regarding the VIA chip set(s):
833    Right now, the SMBus code depends on the Intel PIIX4 chip to handle
834SMBus transactions.  The VIA chip set is NOT supported at this time because
835it forces much of the SMBus protocol to be implemented by software.
836    To implement the SMBus correctly with the VIA chip, it needs to be
837written at a low level to be quick.  A more attractive alternative is to
838use the Bios SMBus interface (not always available nor standard).
839
840    Version 2 supports the VIA chipset, and will support other chipsets.
841Version 1 never will.
842
843
8446.2 The modules won't load, saying 'SMBus not detected'.
845
846    This should no longer be an issue in 1.4.10 and later; it will
847continue loading, but it won't support SMBus-connected devices, of course.
848
849
8506.3 I try to read /proc/sensors, and I get a "No sensor data yet (try again in
851a few moments)" message. Why?
852
853    It takes about 1.5 seconds for the LM78 to update all its sensor
854values.  If we would try to read it before it finished that, you would get
855old garbage instead. So you have to wait 1.5 seconds after the module is
856inserted before you can access /proc/sensors.
857    Module versions 1.3.7 and later let the process sleep if it tries
858to access sensor data right after insertion time, and do not display this
859message anymore.
860
861
8626.4 On my Dell, a LM80 is detected, but all readings are 0!
863
864    This is a bug we have only observed on Dell computers. There is
865probably a problem with the way the SMBus is accessed; but it is not yet
866clear whether the problem is in our code or with the Dells.
867    There are very probably no sensor chips at all on your computer;
868but until somebody contacts Dell about this and tells us the results, we
869can not be sure.
870
871
872---------------------------------------------------------------------------------------
873---------------------------------------------------------------------------------------
874Rev 2.3 (MDS) General update, 20010224
875Rev 2.2 (Frodo) Corrections for lm_sensors 2.4, 19990920
876Rev 2.1 (Frodo) Corrections for lm_sensors 2.2, 19990112
877Rev 2.0 (Frodo) Major revision for lm_sensors 2.1, 19981229
878Rev 1.10 (Frodo) Modified 3.8, updated some other things, 19980924
879Rev 1.9 (Frodo) Added 3.15, 19980906
880Rev 1.8 (Frodo) Added 3.14, 19980905
881Rev 1.7 (Phil) Added 3.13 and some other minor changes, 19980901
882Rev 1.6 (Frodo) Added 4, 4.1, 4.2, 4.3, 4.4, 4.5, 19980901
883Rev 1.5 (Frodo) Added 2.3, 2.4, 3.9, 3.10, 3.11, 19980826
884Rev 1.4 (Frodo) Added some more Winbond information, and 3.5-3.8, 19980817
885Rev 1.3 Added info on the Winbond chip, 19980816
886Rev 1.2 Adapation by Frodo Looijaard, 19980810
887Rev 1.1 Modifications by Philip Edelbrock, 19980809
888Rev 1.0 Written by Philip Edelbrock, 19980803
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