root/lm-sensors/trunk/doc/lm_sensors-FAQ.texi @ 4197

Revision 4197, 64.8 KB (checked in by khali, 8 years ago)

Delete the icspll driver. It was rather useless, not built by default,
supposedly dangerous, and has nothing to do with sensors.

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1\input texinfo.tex    @c -*-texinfo-*-
2
3@c %**start of header
4@setfilename lm_sensors-FAQ.info
5@include version.texi
6@settitle Sensors FAQ for lm_sensors version @value{VERSION}
7@comment %**end of header
8
9@titlepage
10@center @titlefont{This is the FAQ for the @command{lm_sensors} program, @value{VERSION}}
11@sp 3
12@center Copyright (C) 1998 - 2005
13@sp 1
14@center Frodo Looijaard,
15@center Philip Edelbrock,
16@center Mark D. Studebaker,
17@center and
18@center Jean Delvare
19@end titlepage
20
21@ifhtml
22Copyright (C) 1998 - 2005@*
23Frodo Looijaard,@*
24Philip Edelbrock,@*
25Mark D. Studebaker@*
26and@*
27Jean Delvare@*
28@end ifhtml
29
30@dircategory Utilities
31@direntry
32* lm_sensors-FAQ: (lm_sensors-FAQ)           The lm_sensors FAQ
33@end direntry
34
35@summarycontents
36@contents
37
38@ifnottex
39@node Top
40@top lm_sensors
41
42The lm_sensors package includes a collection of modules for general SMBus
43access and hardware monitoring.  NOTE: this requires special support which
44is not in standard 2.2-vintage kernels.
45
46@end ifnottex
47
48@menu
49* Overview::                PC and Sensor Overview
50* Basics::                  Sensor and Bus Basics
51* Installation::            Installation and Management
52* Problems::                Problems
53* Help::                    How to Ask for Help
54* Contribute::              How to Contribute
55* Document Revisions::      Revision History of This Document
56@end menu
57
58
59@node Overview, Basics, Top, Top
60@chapter PC and Sensor Overview
61
62@menu
63* Section 1.1::             What sensors are available on my PC?
64* Section 1.2::             What can a sensor chip like the "LM78" do?
65* Section 1.3::             Where do I find out more about any of these chips?
66@end menu
67
68@node Section 1.1, Section 1.2, , Overview
69@section What sensors are available on my PC?
70
71Most PC's built since late 1997 now come with a
72hardware health monitoring chip. This chip may be accessed via the
73ISA bus or the SMBus, depending on the motherboard.
74
75Some motherboard chipsets, notably the Via 686 and the SiS 5595,
76contain hardware monitor functions.
77
78This FAQ frequently refers to the "LM78". This chip has been
79obsoleted by National Semiconductor. Most motherboards today contain
80a chip with similar functions.
81
82
83@node Section 1.2, Section 1.3, Section 1.1, Overview
84@section What can a sensor chip like the "LM78" do?
85
86The LM78 is a chip made by National Semiconductor which can monitor 7
87voltages (5 positive, 2 negative) from 0 to 4.08V.  The inputs are usually in
88series with voltage dividers which lower the +/- 12V and +/- 5V supplies to
89measurable range.  Therefore, the readings for such inputs need to be
90re-scaled appropriately by software.
91
92The LM78 also has 3 fan speed monitoring inputs, an internal
93temperature sensor, a chassis intrusion sensor, and a couple maskable interrupt
94inputs.  The LM78 can also relay the processor's (P6 or Pent II) VID lines
95which are hardwired and used to indicate to the power regulator (usually on
96the mainboard close to the processor socket/slot) what voltage to supply to
97the processor.
98
99The LM78 can be interfaced to a system via the ISA bus and/or the
100SMBus.
101
102Most other sensor chips have comparable functionality. Each supported
103chip is documented in the @file{doc/chips} directory.
104
105
106@node Section 1.3,  , Section 1.2, Overview
107@section Where do I find out more about any of these chips?
108
109Most semiconductor companies have comprehensive documentation,
110including complete datasheets, on their websites. Analog Devices,
111Dallas Semiconductor, Maxim, and National Semiconductor have the widest selection
112of sensor chips. Their websites are:
113
114@itemize @bullet
115  @item @uref{http://www.analog.com}
116  @item @uref{http://www.dalsemi.com}
117  @item @uref{http://www.maxim-ic.com}
118  @item @uref{http://www.national.com}
119@end itemize
120
121Please see the file @uref{http://www.lm-sensors.org/wiki/UsefulLinks}
122for links to other companies' websites.
123
124
125
126@node Basics, Installation, Overview, Top
127@chapter Sensor and Bus Basics
128
129@menu
130* Section 2.1::             What sensors are available on my PC?
131* Section 2.2::             What can a sensor chip like the "LM78" do?
132* Section 2.3::             Where do I find out more about any of these chips?
133* Section 2.4::             What sensors are available on my PC?
134* Section 2.5::             What can a sensor chip like the "LM78" do?
135* Section 2.6::             Where do I find out more about any of these chips?
136@end menu
137
138
139@node Section 2.1, Section 2.2, , Basics
140@section How are these sensors read?
141
142Sensor chips reside on either the ISA bus, the SMBus, or both.
143See the file @file{doc/chips/SUMMARY} in our package for a list.
144
145To communicate with chips on the ISA bus, the software uses
146simple I/O reads and writes.
147
148To communicate with chips on the SMBus, the software must
149use an SMBus interface device, explained below.
150
151
152@node Section 2.2, Section 2.3, Section 2.1, Basics
153@section What is the SMBus? And the I2C bus?
154
155The SMBus is the "System Management Bus".  More specifically, it is a
1562-wire, low-speed serial communication bus used for basic health monitoring
157and hardware management. It is a specific implementation of the more
158general I2C (pronunciation: I-squared-C) bus. In fact, both I2C devices
159and SMBus devices may be connected to the same (I2C) bus.
160
161The SMBus (or I2C bus) starts at the host controller, used for
162starting transactions on the SMBus.  From the host interface, the
163devices communicated with are the @dfn{slave} devices.  Each slave device has a
164unique 7-bit address which the host uses to refer to that device.
165
166For each supported SMBus host, there is a separate kernel module
167which implements the communication protocol with the host. Some SMBus hosts
168really operate on the SMBus level; these hosts can not cope with pure I2C
169devices. Other hosts are in fact I2C hosts: in this case, we implement
170the SMBus protocol in terms of I2C operations. But these hosts can also
171talk to pure I2C devices.
172
173
174@node Section 2.3, Section 2.4, Section 2.2, Basics
175@section I don't have an ISA bus!
176
177We promise, you do, even if you don't have any old ISA slots.
178The "ISA Bus" exists in your computer even if you don't have ISA slots;
179it is simply a memory-mapped area, 64KB in size (0x0000 - 0xFFFF)
180where many "legacy" functions, such as keyboard and interrupt controllers,
181are found. It isn't necessarily a separate physical bus.
182See the file @file{/proc/ioports} for a list of devices living on
183the "ISA Bus" in your system. If you don't like the term "ISA Bus"
184think "I/O Space".
185
186
187@node Section 2.4, Section 2.5, Section 2.3, Basics
188@section What sensors do processors have?
189
190Most new processors contain a thermal diode on the die itself.
191The electical properties of all diodes and transistors vary
192slightly with temperature. The thermal diode is exceptionally accurate
193because it is directly on the die. Newer temperature sensor chips,
194like the Analog Devices ADM1021 and clones, and the Winbond chips,
195have circuitry for measuring the the electrical properties of
196an external diode and converting this data to a temperature.
197Any sensor chip listed in @file{doc/chips/SUMMARY} in our package which
198has support for more than one temperature supports external temperature sensing.
199
200Older motherboards and processors without this feature generally use
201an LM75 placed close to the processor. This is much less accurate.
202
203The 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
212The P6 (Pentium-Pro) may have an LM75 in or just under the socket.
213P6's also have VID lines.
214
215Pentiums and Pentium w/ MMX do not have VID lines, and sometimes have
216LM75's under the sockets (depends on the mainboard, and how 'modern' the
217mainboard is).
218
219The P2 Xeon was the first Intel processor to include the SMBus
220interface on the P2 Xeon SEC.
221
222
223@node Section 2.5, Section 2.6, Section 2.4, Basics
224@section How often are the sensor values updated?
225
226The LM78, and most other sensor chips like it, reads its sensors one
227by one. A complete scanning sweep will take about 1.5 seconds. The LM78 stops
228readings sensors if you try to access it, so if you access it very often
229(by reading sensor values; writing new limits is safe) it will not find the
230time to update its sensor values at all! Fortunately, the kernel module takes
231care not to do this, and only reads new values each 1.5 seconds. If you
232read the values again, you will get the 'old' values again.
233
234
235@node Section 2.6, , Section 2.5, Basics
236@section How are alarms triggered?
237
238It is possible to monitor each sensor and have an alarm go off if
239it crosses some pre-determined limits.  There are two sorts of interrupts
240which can be generated by sensor chips if this happens (it depends a bit on
241the actual chip if both are supported; the LM80, for example, has only
242IRQ interrupts): IRQ interrupts and SMI interrupts.  IRQ stands for
243Interrupt Request and are the interrupt lines you can find in @file{/proc/interrupts}.
244SMI stands for System Management Interrupt, and is a special interrupt which
245puts the processor in a secure environment independent of any other things
246running.  SMI is currently not supported by the Linux kernel.  IRQs are
247supported, of course.
248
249Even if no interrupt is generated, some bits in a status register
250will be set until the register is read the next time. If the alarm condition
251persists after that, the bits will be set on the next scanning sweep, etc.
252
253Most drivers in our package do not support interrupts at this time.
254
255
256
257@node Installation, Problems, Basics, Top
258@chapter Installation and Management
259
260@menu
261* Section 3.1::     Why so many modules, and how do I cope with them?
262* Section 3.2::     How do I know which chips I own?
263* Section 3.3::     Which modules should I insert?
264* Section 3.4::     Do I need the configuration file @file{/etc/sensors.conf}?
265* Section 3.5::     What about the @samp{No such file or directory} warnings
266* Section 3.6::     I get all kinds of weird compilation errors?
267* Section 3.7::     It still does not compile or patch!
268* Section 3.8::     @command{make install} fails on Mandrake kernels
269* Section 3.9::     I get unresolved symbols when I @command{modprobe} modules
270* Section 3.10::    I2C_DRIVERID_ADM1024 undefined (Red Hat especially)
271@end menu
272
273@node Section 3.1, Section 3.2, , Installation
274@section Why so many modules, and how do I cope with them?
275
276We tried to make this package as modular as possible. This makes it
277easy to add new drivers, and unused drivers will take no precious kernel
278space. On the other hand, it can be a bit confusing at first.
279
280Here are two simple guidelines:
281@itemize
282  @item Run @command{sensors-detect} and do what it tells you.
283  @item Always use @command{modprobe}, not @command{insmod}.
284@end itemize
285
286Further information is in @file{doc/modules}.
287
288
289@anchor{How do I know which chips I own}
290@node Section 3.2, Section 3.3, Section 3.1, Installation
291@section How do I know which chips I own?
292
293We have an excellent program that scans all your hardware.
294It is called @file{sensors-detect} and is installed in @file{/usr/local/sbin}
295by @command{make install}. Just execute this script, and it will tell you.
296
297Chip detection in the drivers is fairly good. That means that it is
298usually harmless to insert more chip drivers than you need. However, this
299can still lead to problems, so we do not recommend it.
300
301If sensors-detect didn't find any sensors, either you don't have
302any, or the ones you have, we don't support. (Look at your motherboard
303for candidates, then @pxref{Help})
304
305
306@anchor{Section 3.2.1}
307@subsection What chips are on motherboard XYZ?
308
309    @strong{!!!!!!!!! YES THIS IS THE MOST FREQUENT QUESTION WE GET !!!!!!!!!}
310
311We have no idea. Here is what you should do:
312@enumerate
313  @item Run sensors-detect.
314@end enumerate
315
316If that doesn't work:
317@enumerate 2
318@item Look at your motherboard.
319@item Check the manufacturer's website or ask their support
320@item Check the @uref{http://mbm.livewiredev.com/, Motherboard Monitor} website and the
321@uref{http://www.lm-sensors.org/wiki/UsefulLinks, "links"}
322page on @uref{http://www.lm-sensors.org, our website} some good cross-references.
323@end enumerate
324
325
326@anchor{Section 3.2.2}
327@subsection Do you support motherboard XYZ?
328
329We don't support boards, we support chips. @xref{Section 3.2.1, What chips are on motherboard XYZ}.
330
331
332@anchor{Section 3.2.3}
333@subsection Do you support chip XYZ?
334
335This we have good answers for.
336@itemize
337@item Sorted by Manufacturer:   @file{README}
338@item Sorted by Manufacturer:   @uref{http://www.lm-sensors.org/wiki/Devices}
339@item Sorted by Sensor Driver:  @file{doc/chips/SUMMARY}
340@end itemize
341
342
343@anchor{Section 3.2.4}
344@subsection Anybody working on a driver for chip XYZ?
345
346Newest Driver Status: @uref{http://www.lm-sensors.org/wiki/Devices}
347
348
349@node Section 3.3, Section 3.4, Section 3.2, Installation
350@section Which modules should I insert?
351
352@command{sensors-detect} will tell you. Take the @command{modprobe} lines it
353recommends and paste them into the appropriate @file{/etc/rc.d/xxxx} file
354to be executed at startup.
355
356You need one module for each sensor chip and bus adapter you own;
357if there are sensor chips on the ISA bus, you also need @file{i2c-isa.o}.
358for each type of chip you own. That's all. On my computer, I could use the
359following lines:
360@itemize
361@item @command{modprobe i2c-isa}
362@item @command{modprobe i2c-piix4}
363@item @command{modprobe lm78}
364@item @command{modprobe lm75}
365@item @command{modprobe i2c-dev}
366@item @command{sensors -s}
367@end itemize
368
369
370@node Section 3.4, Section 3.5, Section 3.3, Installation
371@section Do I need the configuration file @file{/etc/sensors.conf}?
372
373Yes, for any applications that use @file{libsensors,} including the
374@command{sensors} application included in our package.
375It tells libsensors how to translate the values the chip
376measures to real-world values. This is especially important for voltage
377inputs. The default configuration file should usually do the trick.
378It is automatically installed as @file{/etc/sensors.conf}, but it will not
379overwrite any existing file with that name.
380
381
382@anchor{Section 3.4.1}
383@subsection The labels for the voltage and temperature readings in @command{sensors} are incorrect!
384
385Every motherboard is different. You can customize the labels
386in the file @file{/etc/sensors.conf}. That's why it exists!
387The default labelling (in @file{lib/chips.c} and @file{/etc/sensors.conf}) is just
388a template.
389
390
391@anchor{Section 3.4.2}
392@subsection The min and max for the readings in @command{sensors} are incorrect!
393
394You can customize them in the file @file{/etc/sensors.conf}. See above.
395
396
397@anchor{Section 3.4.3}
398@subsection The min and max settings in @file{/etc/sensors.conf} didn't take effect!
399
400You forgot to run @command{sensors -s}. See above.
401
402
403@anchor{Section 3.4.4}
404@subsection One sensor isn't hooked up on my board!
405
406Use an @command{ignore} line in @file{/etc/sensors.conf} so it isn't
407displayed in @command{sensors}.
408
409
410@anchor{Section 3.4.5}
411@subsection I need help with @file{sensors.conf}!
412
413There is detailed help at the top of that file.
414
415
416@anchor{Section 3.4.6}
417@subsection Do you have a database of @file{sensors.conf} entries for specific boards?
418
419No. Good idea though. If you would like to set one up on your website
420send us mail and we will set up a link to it.
421
422
423@node Section 3.5, Section 3.6, Section 3.4, Installation
424@section What about the @samp{No such file or directory} warnings when I compile?
425
426Don't worry about them. The dependency files (which tell which
427files should be recompiled when certain files change) are created
428dynamically. They are not distributed with the package. The @command{make} program
429notices they are not there, and warns about that - and the first thing
430it will do is generate them. So all is well.
431
432
433@node Section 3.6, Section 3.7, Section 3.5, Installation
434@section I get all kinds of weird compilation errors?
435
436Check that the correct i2c header files are used. Depending on
437how you installed, they should be under either @file{/usr/local/include} or
438@file{/usr/src/linux*/include}. Try to edit the @file{Makefile} for the other setting.
439
440
441@anchor{Section 3.6.1}
442@subsection @samp{No rule to make target xxxx needed by xxxx} - how to fix?
443
444@itemize
445@item @xref{Section 3.6, I get all kinds of weird compilation errors}, also try @command{make clean} in @file{lm_sensors}.
446@item If that doesn't work, try @command{make clean} in @file{i2c}.
447@item If that doesn't work, try @command{make clean} in the kernel.
448@item Also make sure @file{/usr/include/linux} points to @file{/usr/src/linux/include/linux}.
449@end itemize
450
451
452@node Section 3.7, Section 3.8, Section 3.6, Installation
453@section It still does not compile or patch!
454
455Have you installed the matching version of the i2c package? Remember,
456compilation is not enough, you also need to install it for the header
457files to be found!
458
459If you want to patch the kernel, you will have to apply the i2c
460patches first!
461
462
463@node Section 3.8, Section 3.9, Section 3.7, Installation
464@section @command{make install} fails on Mandrake kernels
465
466Mandrake uses a non-standard @file{version.h} file which confuses our @file{Makefile}.
467Edit our @file{Makefile} on the @code{MODDIR :=} line to hard-code the module directory.
468
469
470@node Section 3.9, Section 3.10, Section 3.8, Installation
471@section I get unresolved symbols when I @command{modprobe} modules (Red Hat especially)
472
473Example:
474@example
475*** Unresolved symbols in /lib/modules/2.4.5/kernel/drivers/i2c/i2c-i810.o
476i2c_bit_add_bus_R8c3bc60e
477i2c_bit_del_bus_R92b18f49
478@end example
479
480You can also run @command{depmod -a -e} to see all unresolved symbols.
481
482
483These are module versioning problems. Generally you did not compile
484against the kernel you are running. Sometimes the Red Hat source you
485have is not for the kernel you are running.
486You must compile our package against the source for the kernel you
487are running with something like @command{make LINUX=/usr/src/linux-2.4.14}.
488
489
490Try the following to be sure:
491
492@itemize
493@item @command{nm --extern MODULE.o}
494Filter out the kernel symbols, like @code{kmalloc}, @code{printk} etc. and note the
495number code behind them, like @code{printk_R1b7d4074}. If there is no numeric
496code after them, note this too.
497@item @command{grep SYMBOL /proc/ksyms}
498Substitute SYMBOL by the basename of the symbols above, like @code{kmalloc},
499@code{printk} etc. Note the number code behind them, or the lack thereof.
500@item Compare both sets of symbols. Are they the same? If so, the problem
501lies somewhere else. Are they different? If so, you have a module
502versioning problem.
503@end itemize
504
505
506@node Section 3.10, , Section 3.9, Installation
507@section I2C_DRIVERID_ADM1024 undefined (Red Hat especially)
508
509In some versions of Redhat, an RPM is included to provide i2c support.
510However, this RPM does not place the header files in the kernel directory
511structure.  When you update kernels, they may persist.  To get rid of
512these obsolete header files, at a command prompt:
513
514@enumerate
515@item @command{rpm -qa | grep i2c}
516@item Look for @file{kernel-i2c,} or a similar rpm in the output
517@item <as root>
518@command{rpm -ev kernel-i2c} (or the name of the similar package)
519If this complains about dependencies, you can try adding
520@command{--nodeps}, but this *MAY* break something else.  Not likely,
521as you have upgraded kernels, and nothing should be using the
522old i2c stuff anymore anyway.  Just don't use it with abandon.
523@item Try (in the build directory of @file{lm_sensors)}
524@example
525@command{make clean}
526@command{make}
527@end example
528@item @emph{If} you still have problems, you may have to replace the include
529paths in the @file{.c/.h} files with absolute paths to the header files.
530More of a workaround than a real fix, but at least you can get it
531to work.
532@end enumerate
533
534
535@node Problems, Help, Installation, Top
536@chapter Problems
537
538@menu
539* Section 4.1::         My fans report exactly half/double their values?
540* Section 4.2::         Why do my two LM75's report "-48 degrees"?
541* Section 4.3::         Why do I have two Vcore readings?
542* Section 4.4::         How do those ALARMS work?
543* Section 4.5::         My voltage readings seem to drift a bit. What's wrong?
544* Section 4.6::         Some measurements are way out of range. What happened?
545* Section 4.7::         What are VID lines? Why is the VID reading wrong?
546* Section 4.8::         Sensor are only updated each second or so. Why?
547* Section 4.9::         It takes a second before reading sensor results. Why?
548* Section 4.10::        Can I be alerted when an ALARM occurs?
549* Section 4.11::        SMBus transactions on my PIIX4 simply don't work. Why?
550* Section 4.12::        My BIOS reports a higher CPU temperature than you!
551* Section 4.13::        I read strange values from the raw @file{/proc} files!
552* Section 4.14::        How do I set new limits?
553* Section 4.15::        Some sensors are doubly detected?
554* Section 4.16::        I ran sensors-detect, but now I get strange readings?!
555* Section 4.17::        Bad readings from particular chips
556* Section 4.18::        How do I configure two chips (LM87) differently?
557* Section 4.19::        Dmesg says @samp{Upgrade BIOS}! I don't want to!
558* Section 4.20::        Sensors says @samp{Can't access procfs/sysfs file}
559* Section 4.21::        Sensors says @samp{No sensors found!}
560* Section 4.22::        Sensors output is not correct!
561* Section 4.23::        What is at I2C address XXX?
562* Section 4.24::        Sensors-detect doesn't work at all
563* Section 4.25::        Sensors says @samp{Error: Line xxx: zzzzzzz}
564* Section 4.26::        Sensors only gives the name, adapter, and algorithm!
565* Section 4.27::        Sensors says @samp{ERROR: Can't get xxxxx data!}
566* Section 4.28::        Sensors doesn't find any sensors, just eeproms.
567* Section 4.29::        Inserting modules hangs my board
568* Section 4.30::        Inserting modules slows down my board
569* Section 4.31::        Problems on particular motherboards
570* Section 4.32::        Problems on particular systems
571* Section 4.33::        Problems on 2.6 kernels
572@end menu
573
574
575@node Section 4.1, Section 4.2, , Problems
576@section My fans report exactly half/double their values compared to the BIOS?
577
578The problem with much of the sensor data is that it is impossible to
579properly interpret some of the readings without knowing what the hardware
580configuration is.  Some fans report one 'tick' each rotation, some report
581two 'ticks' each rotation. It is easy to resolve this through the
582configuration file @file{/etc/sensors.conf}:
583
584@example
585chip lm78-*             # Or whatever chip this relates to
586compute fan1 2*@@,@@/2    # This will double the fan1 reading
587                        # -- or --
588compute fan1 @@/2,2*@@    # This will halve the fan1 reading
589@end example
590
591See @file{doc/fan-divisors} in our package for further information.
592
593
594@anchor{Fans sometimes/always read 0!}
595@subsection Fans sometimes/always read 0!!
596
597You may not have a three-wire fan, which is required.
598
599You may need to increase the 'fan divisor'. See @file{doc/fan-divisors}
600in our package for further information.
601
602
603@anchor{I doubled the fan divisor and the fan still reads 7000}
604@subsection I doubled the fan divisor and the fan still reads 7000!
605
606Believe it or not, doubling the 'fan divisor' will not halve
607the fan reading. You have to add a compute line in @file{/etc/sensors.conf}.
608@xref{Section 4.1, My fans report exactly half/double their values compared to the BIOS},
609and see @file{doc/fan-divisors} in our package for further information.
610
611
612@node Section 4.2, Section 4.3, Section 4.1, Problems
613@section Why do my two LM75's report "-48 degrees"?
614
615For starters, those aren't LM75's.  Your mainboard actually has the
616Winbond W83781D which emulates two LM75's, but many systems which use the
617Winbond chip (such as the Asus P2B) don't have the thermo-resisters connected
618to the chip resulting in these strange -48 degree readings.
619
620In upcoming versions, you will be able to disable non-interesting
621readings.
622
623
624@node Section 4.3, Section 4.4, Section 4.2, Problems
625@section Why do I have two Vcore readings, I have only one processor!
626
627The LM78 has seven voltage sensors. The default way of
628connecting them is used in the configuration file. This includes a VCore2,
629even if you do not have one. You can easily edit the configuration file
630to give it another name, or make this reading disappear using
631an @command{ignore} line.
632
633Note that Vcore2 is often the same as Vcore on motherboards which
634only support one processor. Another possibility is that Vcore2 is not
635connected at all and will not have a valid reading at all.
636A third possibility, is that Vcore2 monitors something
637else, so you should not be too surprised if the values are completely
638different.
639
640
641@node Section 4.4, Section 4.5, Section 4.3, Problems
642@section How do those ALARMS work? The current value is within range but there is still an ALARM warning!
643
644The ALARM indications in @command{sensors} are those reported by the
645sensor chip itself. They are NOT calculated by @command{sensors}. @command{sensors}
646simply reads the ALARM bits and reports them.
647
648An ALARM will go off when a minimum or maximum limit is crossed.
649The ALARM is then latched - that is, it will stay there until the
650chip's registers are next accessed - which will be the next time
651you read these values, but not within (usually) 1.5 seconds since the last
652update.
653
654Reading the registers clears the ALARMS, unless the current
655value is still out of range.
656
657The purpose of this scheme is to tell you if there has been
658a problem and report it to the user. Voltage or temperature spikes
659get detected without having to read the sensor chip hundreds of times
660a second. The implemetation details depend a bit on the kind of chip.
661See the specific chip documentation in @file{doc/chips} and the
662chip datasheet for more information.
663
664
665@node Section 4.5, Section 4.6, Section 4.4, Problems
666@section My voltage readings seem to drift a bit. Is something wrong?
667
668No, probably not. If your motherboard heats up a bit, the sensed
669voltages will drift a bit. If your power supply is loaded (because a disk
670gets going, for example), the voltages may get a bit lower. Heavy
671processor activity, in particular, dramatically increases core voltage
672supply load which will often cause variation in the other supplies.
673As long as they stay within a sensible range (say 5% of the nominal value
674for CPU core voltages, and 10% for other voltages), there is no
675reason to worry.
676
677
678@node Section 4.6, Section 4.7, Section 4.5, Problems
679@section Some measurements are way out of range. What happened?
680
681Each module tries to set limits to sensible values on initialization,
682but a module does not know how a chip is actually connected. This is
683described in the configuration file, which is not read by kernel modules.
684So limits can be strange, if the chip is connected in a non-standard way.
685
686Readings can also be strange; there are several reasons for this.
687Temperature sensors, for example, can simply not be present, even though
688the chip supports them. Also, it can be that the input is used in a
689non-standard way. You can use the configuration file to describe how this
690measurement should be interpreted; see the comments the example file for
691more information.
692
693@anchor{-5V and -12V readings are way out of range!}
694@subsection -5V and -12V readings are way out of range!
695
696It's very frequent that negative voltage lines are not wired because
697motherboard manufacturers don't think they're worth monitoring
698(they are mostly unused these days). You can just add
699@command{ignore inN} lines to @file{/etc/sensors.conf} to hide them.
700
701Another possibility is that these lines are used to monitor different
702voltages. Only the motherboard manufacturer can tell for sure. Taking
703a look at what voltage values the BIOS displays may provide valuable
704hints though.
705
706
707@node Section 4.7, Section 4.8, Section 4.6, Problems
708@section What are VID lines? Why is the VID reading wrong?
709
710These describe the core voltage for your processor. They are
711supported for most processors, however they are not always
712correctly connected to the sensor chip, so the readings may be invalid.
713A reading of 0V, +3.5V or +2.05V is especially suspect.
714If this is the case, add a line @command{ignore vid} to @file{/etc/sensors.conf},
715and change the min and max settings for the Processor Core voltage
716(often in0_min and in0_max) in that file so that they don't depend on vid.
717
718The CPU nominal voltage is computed from VID lines according to a formula
719that depends on the CPU type. Most chips that report a VID value can be
720configured to use either VRM 8.2 (for Pentium III) or VRM 9.0 (for Pentium 4
721and Athlon). You chose which one you want through @file{/etc/sensors.conf}.
722See @file{doc/vid} for more information.
723
724
725@node Section 4.8, Section 4.9, Section 4.7, Problems
726@section I read sensor values several times a second, but they are only updated only each second or so. Why?
727
728If we would read the registers more often, it would not find the
729time to update them. So we only update our readings once each 1.5 seconds
730(the actual delay is chip-specific; for some chips, it may not be needed
731at all).
732
733
734@node Section 4.9, Section 4.10, Section 4.8, Problems
735@section It sometimes seems to take almost a second before I see the sensor reading results. Why?
736
737ISA bus access is fast, but SMBus access is really slow. If you have
738a lot of sensors, it just takes a lot of time to access them. Fortunately,
739this has almost no impact on the system as a whole, as another job can run
740while we are waiting for the transaction to finish.
741
742
743@node Section 4.10, Section 4.11, Section 4.9, Problems
744@section Can I be alerted when an ALARM occurs?
745
746No, you can't; and it may well be never supported.
747
748Almost no mainboard we have encountered have actually connected the
749IRQ-out pin of sensor chips. That means that we could enable IRQ reporting, but
750nothing would happen. Also, even if a motherboard has it connected, it is
751unclear what interrupt number would be triggered. And IRQ lines are a scarce
752facility, which means that almost nobody would be able to use it anyway.
753
754The SMI interrupt is only available on a few types of chips. It is
755really a very obscure way to handle interrupts, and supporting it under Linux
756might be quite hard to do.
757
758Your best bet would be to poll the alarm file with a user-land daemon
759which alerts you if an alarm is raised. I am not aware of any program which
760does the job, though you might want to examine one of the graphical monitor
761programs under X, see @uref{http://www.lm-sensors.org/wiki/UsefulLinks} for addresses.
762
763
764@node Section 4.11, Section 4.12, Section 4.10, Problems
765@section SMBus transactions on my PIIX4 simply don't work (timeouts happen).  Why?
766
767Some chips which mainboard makers connect to the SMBus are not SMBus
768devices.  An example is the 91xx clock generator chips.  When read, these
769devices can lock up the SMBus until the next hard reboot.  This is because
770they have a similar serial interface (like the I2C), but don't conform to
771Intel's SMBus standard.
772
773Why did they connect these devices to the SMBus if they aren't
774compatible?  Good question! :')  Actually, these devices may support being
775written to, but lock things up when they are read.
776
777
778@node Section 4.12, Section 4.13, Section 4.11, Problems
779@section My BIOS reports a much higher CPU temperature than your modules!
780
781We display the actual temperature of the sensor. This may not be the
782temperature you are interested in, though.  If a sensor should measure
783the CPU temperature, it must be in thermal contact with it.  In practice,
784it may be just somewhere nearby. Your BIOS may correct for this (by adding,
785for example, thirty degrees to the measured temperature).  The correction
786factor is regrettably different for each mainboard, so we can not do this
787in the module itself. You can do it through the configuration file, though:
788
789@example
790chip lm75-*-49                      # Or whatever chip this relates to
791label temp "Processor"
792compute temp @@*1.2+13,(@@-13)/1.2    # Or whatever formula
793@end example
794
795However, the offset you are introducing might not be necessary. If you
796tried to have Linux idle temperature and BIOS "idle" temperature match,
797you may be misguided.
798We have a Supermicro (370DLE) motherboard and we know
799that its BIOS has a closed, almost undelayed while(1) loop that
800keeps the CPU busy all the time. Linux reads 26 degrees idle, BIOS reads
80138 degrees. Linux at full load is in the 35-40 degrees range so this
802makes sense.
803
804@node Section 4.13, Section 4.14, Section 4.12, Problems
805@section I try to read the raw @file{/proc} files, but the values are strange?!?
806
807Remember, these values do not take the configuration file
808@file{compute} lines in account. This is especially obvious for voltage readings
809(usually called in? or vin?). Use a program linked to libsensors (like
810the provided @command{sensors} program) instead.
811
812
813@node Section 4.14, Section 4.15, Section 4.13, Problems
814@section How do I set new limits?
815
816Change the limit values in @file{/etc/sensors.conf} and then run
817@command{sensors -s}.
818
819
820@anchor{I set new limits and it didnt work}
821@subsection  I set new limits and it didn't work?
822
823You forgot to run @command{sensors -s}. Put it in a @file{/etc/rc.d/...} file
824after the modprobe lines to run at startup.
825
826
827@node Section 4.15, Section 4.16, Section 4.14, Problems
828@section Some sensors are doubly detected?
829
830Yes, this is still a problem. It is partially solved by alias detection
831and confidence values in sensors-detect, but it is really tough.
832
833Double detections can be caused by two things:
834sensors can be detected to both the ISA and the SMBus (and if you have
835loaded the approprate adapter drivers, it will be detected on both), and
836some chips simulate other chips (the Winbond W83781D simulates LM75 chips
837on the SMBus, for example). Remove the offending adapter or chip driver, or
838run sensors-detect and add the @command{ignore=} modprobe parameters it suggests.
839
840
841@node Section 4.16, Section 4.17, Section 4.15, Problems
842@section I ran sensors-detect, but now I get very strange readings?!?
843
844Your SMBus (PIIX4?) is probably crashed or hung. There are some mainboards
845which connect a clock chip to the SMBus. Unfortunately, this clock chip
846hangs the PIIX4 if it is read (it is an I2C device, but not SMBus compatible).
847We have found no way of solving this, except for rebooting your computer.
848Next time when you run sensors-detect, you may want to exclude addresses
8490x69 and/or 0x6a, by entering @kbd{s} when you are asked whether you want to
850scan the PIIX4.
851
852
853@node Section 4.17, Section 4.18, Section 4.16, Problems
854@section Bad readings from particular chips
855
856See below for some particularly troublesome chips.
857Also be sure and check @file{doc/chips/xxxxx} for the particular driver.
858
859
860@anchor{Bad readings from the AS99127F}
861@subsection Bad readings from the AS99127F!
862
863The Asus AS99127F is a modified version of the Winbond W83781D.
864Asus will not release a datasheet. The driver was developed by tedious
865experimentation. We've done the best we can. If you want to make adjustments
866to the readings please edit @file{/etc/sensors.conf.} Please don't ask us to
867fix the driver. Ask Asus to release a datasheet.
868
869
870@anchor{Bad readings from the VIA 686A}
871@subsection Bad readings from the VIA 686A!
872
873The Via 686A datasheet is incomplete.
874Via will not release details. The driver was developed by tedious
875experimentation. We've done the best we can. If you want to make adjustments
876to the readings please edit @file{/etc/sensors.conf.} Please don't ask us to
877fix the driver. Ask Via to release a better datasheet.
878Also, don't forget to @command{modprobe i2c-isa}.
879
880
881@anchor{Bad readings from the MTP008}
882@subsection Bad readings from the MTP008!
883
884The MTP008 has programmable temperature sensor types.
885If your sensor type does not match the default, you will have to change it.
886See @file{doc/chips/mtp008} for details.
887Also, MTP008 chips seem to randomly refuse to respond, for
888unknown reasons. You can see this as 'XX' entries in i2cdump.
889
890
891@anchor{Bad temperature readings from the SIS5595}
892@subsection Bad temperature readings from the SIS5595!
893
894This chip can use multiple thermistor types and there are also
895two different versions of the chip. We are trying to get the driver
896working better and develop formulas for different thermistors
897but we aren't there yet. Sorry.
898Also, many times the chip isn't really a sis5595 but it was
899misidentified. We are working on improving that too.
900
901
902@anchor{Bad readings from a w8378[12]d}
903@subsection Bad readings from a w8378[12]d!
904
905Do you own an ASUS motherboard?  Perhaps your chip is being
906misidentified.  Look on the motherboard (or at
907@uref{http://mbm.livewiredev.com}) for a 'Winbond' or Asus chip.
908Often the real device is an Asus as99127f. If so, the driver can be
909forced to recognize the as99127f with
910@command{force_as99127f=BUS,0x2d} where @code{BUS} is your i2c bus number.
911Cat /proc/bus/i2c to see a list of bus numbers.
912Read the w83781d module documentation (@file{doc/chips/w83781d})
913for more details.
914
915
916@anchor{Bus hangs on Ali 1543 on Asus P5A boards}
917@subsection Bus hangs on Ali 1543 on Asus P5A boards!
918
919The SMBus tends to hang on this board and it seems to get worse
920at higher temperatures. Use ISA accesses to reliably use the w83781d
921monitor chip on this board and use the @command{ignore=1,0x2d} or similar option
922to the w83781d module to prevent i2c accesses.
923
924
925@anchor{Bad readings from LM75}
926@subsection Bad readings from LM75!
927
928The LM75 detection is poor and other hardware is often misdetected
929as an LM75. Figure out what you really have @xref{Section 3.2.1, What chips are on motherboard XYZ}.
930
931
932@anchor{Bad readings from LM78}
933@subsection Bad readings from LM78!
934
935The LM78 is no longer manufactured by National Semiconductor.
936You probably don't have a real LM78 but something similar that we
937do not recogize or support. Figure out what you really have @xref{Section 3.2.1, What chips are on motherboard XYZ}.
938
939
940@anchor{Bad readings from LM80}
941@subsection Bad readings from LM80!
942
943The LM80 detection is poor and other hardware is often misdetected
944as an LM80. Figure out what you really have @xref{Section 3.2.1, What chips are on motherboard XYZ}.
945
946
947@node Section 4.18, Section 4.19, Section 4.17, Problems
948@section How do I configure two chips (LM87) differently?
949
950There is a SuperMicro board with two LM87's on it that are
951not hooked up in the same way, so they need different defaults.
952For example, both CPU temperatures go to one LM87.
953
954Make two different sections in @file{/etc/sensors.conf} as follows:
955@example
956chip "lm87-i2c-*-2c"
957    put configuration for the chip at 0x2c here
958chip "lm87-i2c-*-2d"
959    put configuration for the chip at 0x2d here
960@end example
961
962There is a commented example in @file{sensors.conf.eg} which should
963be helpful.
964
965
966@node Section 4.19, Section 4.20, Section 4.18, Problems
967@section Dmesg says @samp{Upgrade BIOS}! I don't want to!
968
969If the problem is a PCI device is not present in @command{lspci}, the solution
970is complex. For the ALI M7101 device, there is a solution which uses the
9712.4 kernel's @command{hotplug} facility. See @file{prog/hotplug} in our package.
972For other PCI devices, you can try to modify
973the m7101 solution in @file{prog/hotplug}.
974
975
976If dmesg says @samp{try force_addr}, see below. Other drivers generally do not
977support the force_addr parameter. Sorry. Check the documentation
978for your driver in @file{doc/[chips,busses]} and if we don't support it
979you can send us your request.
980
981
982@anchor{Dmesg says use force_addr=0xaddr! What address do I use}
983@subsection Dmesg says @samp{use force_addr=0xaddr}! What address do I use?
984
985If the problem is a PCI device whose base address is not set,
986you may be able to set the address with a force parameter. The via686a
987and sis5595 chip drivers, and some bus drivers, support the command line
988@command{modprobe via686a force_addr=0xADDRESS} where ADDRESS
989is the I/O address. You must select an address that is not in use.
990@command{cat @file{/proc/ioports}} to check (carefully) for conflicts. A high number like
9910xf000 is generally safe.
992
993
994@node Section 4.20, Section 4.21, Section 4.19, Problems
995@section Sensors says @samp{Can't access procfs/sysfs file}
996
997@itemize
998@item Linux 2.6
999@itemize
1000@item Did you @command{modprobe i2c_sensor}? Check @command{lsmod}.
1001@item Do you have sysfs support in your kernel and @file{/sys} mounted (is @file{/sys} there and populated)?
1002Create /sys with @command{mkdir /sys} if needed. Then add the following line to @file{/etc/fstab}:
1003@example
1004sys              /sys             sysfs       default          0   0@end example
1005and @command{mount /sys}.
1006@end itemize
1007@item Linux 2.4
1008@itemize
1009@item Did you @command{modprobe i2c-proc}? Check @command{lsmod}.
1010@item Do you have procfs support in your kernel and @file{/proc} mounted (is @file{/proc} there and populated)?
1011Create /proc with @command{mkdir /proc} if needed. Then add the following line to @file{/etc/fstab}:
1012@example
1013proc             /proc            proc        defaults         0   0@end example
1014and @command{mount /proc}.
1015@end itemize
1016@item If you did @command{sensors -s}, did you run it as root?
1017@end itemize
1018
1019
1020@node Section 4.21, Section 4.22, Section 4.20, Problems
1021@section Sensors says @samp{No sensors found!}
1022
1023@itemize
1024@item Did @command{sensors-detect} find sensors? (If not @pxref{Sensors-detect doesnt find any sensors})
1025@item Did you do what @command{sensors-detect} said?
1026@item Did you @command{modprobe} your sensor modules?
1027@item Did you @command{modprobe} your I2C adapter modules?
1028@item Did you @command{modprobe i2c-isa} if you have ISA sensor chips?
1029@item Check @command{lsmod}.
1030@end itemize
1031
1032
1033@node Section 4.22, Section 4.23, Section 4.21, Problems
1034@section Sensors output is not correct!
1035
1036    What specifically is the trouble?
1037@itemize
1038@item Labels: @xref{Section 3.4.1, The labels for the voltage and temperature readings in sensors are incorrect}.
1039@item Min/max readings: @xref{Section 3.4.2, The min and max for the readings in sensors are incorrect}, and @xref{Section 3.4.3, The min and max settings didnt take effect}.
1040@item AS99127F: @xref{Section 4.16, I ran sensors-detect but now I get very strange readings?}.
1041@item Via 686A: @xref{Section 4.16, I ran sensors-detect but now I get very strange readings?}.
1042@item Other specific chips: @xref{Section 4.16, I ran sensors-detect but now I get very strange readings?}.
1043@item No output for a particular sensors chip: @xref{Section 5.3, What to do if it inserts but nothing happens}.
1044@item No output at all: @xref{Section 4.21, Sensors says No sensors found}, @xref{Section 5.3, What to do if it inserts but nothing happens}.
1045@item Completely bad output for a particular sensor chip: @xref{Section 5.4, What to do if I read only bogus information}.
1046@item One particular sensor readings:
1047@itemize
1048@item Maybe it isn't hooked up? - tell 'sensors' to ignore it. @xref{Section 3.4.4, One sensor isnt hooked up on my board}.
1049@item Maybe it is hooked up differently on your motherboard? - adjust @file{sensors.conf} calculation.
1050@end itemize
1051@end itemize
1052
1053@node Section 4.23, Section 4.24, Section 4.22, Problems
1054@section What is at I2C address XXX?
1055
1056In general, we don't know. Start by running @command{sensors-detect}.
1057If it doesn't recognize it, try running @command{i2cdump}. A partial list
1058of manufacturers' IDs are at the bottom of @file{doc/chips/SUMMARY}.
1059
1060
1061@anchor{What is at I2C address 0x69}
1062@subsection What is at I2C address 0x69?
1063
1064A clock chip. Often, accessing these clock chips in the wrong
1065way will instantly crash your computer. Sensors-detect carefully
1066avoids these chips, and you should do too.  You have been warned.
1067
1068
1069@anchor{What is at I2C addresses 0x50 - 0x57}
1070@subsection What is at I2C addresses 0x50 - 0x57?
1071
1072EEPROMs on your SDRAM DIMMs. Load the eeprom module to
1073look at some basic data in @command{sensors} or use the program
1074@command{prog/eeprom/decode-dimms.pl} to get more information than you ever wanted.
1075
1076
1077@anchor{What is at I2C addresses 0x30 - 0x37}
1078@subsection What is at I2C addresses 0x30 - 0x37?
1079
1080These are often 'shadows' of your EEPROMs on your SDRAM DIMMs
1081at addresses 0x50 - 0x57. They are the 'software write-protect'
1082registers of the SDRAM Serial Presence Detect EEPROMs.
1083If you try and
1084do a @command{i2cdump} on them to read the location, you won't get anything,
1085because they contain a single write-only register.
1086This register can be used to permanently
1087write-protect the contents of the eeprom.
1088
1089
1090@node Section 4.24, Section 4.25, Section 4.23, Problems
1091@section Sensors-detect doesn't work at all
1092
1093It could be many things. What was the problem? @xref{Section 4.31, Problems on particular motherboards}.
1094
1095
1096@anchor{Sensors-detect says "Couldnt open /proc/bus/i2c?!?"}
1097@subsection Sensors-detect says "Couldn't open /proc/bus/i2c?!?"
1098
1099You don't have i2c support in your kernel, or the i2c-core module
1100was not loaded and you did not run sensors-detect as root.
1101
1102
1103@anchor{Sensors-detect says "Cant open /dev/i2c[-/]0"}
1104@subsection Sensors-detect says "Can't open /dev/i2c[-/]0"
1105
1106Your @file{/dev/i2c-0,} @file{/dev/i2c0}, or @file{/dev/i2c/0} files do not exist
1107or you did not run @command{sensors-detect} as root.
1108Run the script @command{prog/mkdev/mkdev.sh} to create the @file{/dev/i2c-x} files.
1109Run @command{devfs} in the kernel to get the @file{/dev/i2c/x} files.
1110
1111
1112@anchor{Sensors-detect doesnt find any sensors}
1113@subsection Sensors-detect doesn't find any sensors!
1114
1115Either
1116@enumerate
1117@item The board doesn't have any sensors.
1118@item We don't support the sensors on the board.
1119@item The sensors it has are on an I2C bus connected to an I2C bus adapter that we don't support.
1120@item You don't have the latest version of lm_sensors.
1121@end enumerate
1122
1123But in any case you should figure out what is on the board:
1124@enumerate
1125@item Look at your motherboard.
1126@item Check the manufacturer's website.
1127@item Check the @uref{http://mbm.livewiredev.com/, Motherboard Monitor} website.
1128@end enumerate
1129
1130When you know what chips you have, check the
1131@uref{http://www.lm-sensors.org/wiki/Devices, Driver Status} web page to
1132see if support has been added for your chip in a later release or in SVN.
1133
1134
1135@node Section 4.25, Section 4.26, Section 4.24, Problems
1136@section Sensors says @samp{Error: Line xxx: zzzzzzz}
1137
1138These are errors from the libsensors library in
1139reading the @file{/etc/sensors.conf} configuration file. Go to that line
1140number and fix it. If you have a parse error, perhaps you have
1141to put the feature name in double quotes.
1142
1143
1144@node Section 4.26, Section 4.27, Section 4.25, Problems
1145@section Sensors only gives the name, adapter, and algorithm for my chip
1146
1147If @command{sensors} only says this, for example, and doesn't
1148provide any actual data at all:
1149
1150@example
1151it87-isa-0290
1152Adapter: ISA adapter
1153Algorithm: ISA algorithm
1154@end example
1155
1156Your chip is not currently supported by @command{sensors} and so all it
1157does is print out that information. Get the latest release
1158and be sure you are running the @command{sensors} program it installed
1159and not some older @command{sensors}.
1160
1161
1162@node Section 4.27, Section 4.28, Section 4.26, Problems
1163@section Sensors says @samp{ERROR: Can't get xxxxx data!}
1164
1165@itemize
1166@item (Linux 2.6) Make sure you are using one of the
1167@uref{http://www.lm-sensors.org/wiki/Kernel2.6,
1168recommended kernel/lm_sensors combination}.
1169@item You have a @file{libsensors}/@command{sensors} mismatch.
1170@command{sensors} is unable to
1171get a data entry from @file{libsensors}. You probably have an
1172old @file{libsensors} in your @file{/etc/ld.so.conf} path.
1173Make sure you did (as root) a @command{make install} (Linux 2.4) or
1174@command{make user_install} (Linux 2.6) followed by a @command{ldconfig}.
1175Then check the output of @command{ldconfig -v | grep libsensors} to
1176verify that there is only ONE @file{libsensors} entry and that it matches
1177the @file{libsensors} that was built in the @file{lib/} directory in @file{lm_sensors2}.
1178@end itemize
1179
1180
1181@node Section 4.28, Section 4.29, Section 4.27, Problems
1182@section Sensors doesn't find any sensors, just eeproms.
1183
1184@xref{Section 4.24, Sensors-detect doesnt work at all}, if @command{sensors-detect} failed to find any sensors.
1185
1186If @command{sensors-detect} did find sensors, did you insert your modules? For chips on the ISA
1187bus, did you insert i2c-isa?
1188
1189@xref{Section 5.2, What to do if a module wont insert}, if the modules didn't insert,
1190also @ref{Section 4.21, Sensors says No sensors found}.
1191
1192
1193@node Section 4.29, Section 4.30, Section 4.28, Problems
1194@section Inserting modules hangs my board
1195
1196There are several possible causes:
1197@enumerate
1198@item Bus driver problems. Insert the bus driver first, before you have inserted any chip drivers, to verify.
1199@item Wrong chip driver. Verify that you have a chip supported by the chip driver, see @ref{Section 3.2.1, What chips are on motherboard XYZ}.
1200@item The chip driver is reinitializing the chip, which undoes critical initialization done by the BIOS.  Try the parameter @command{init=0} for the w83781d driver; this is the only driver supporting this parameter.
1201@item Some chips on the bus don't like to be probed at all.  After inserting the bus driver (but not the chip drivers), run @command{i2cdetect} on the bus, then @command{i2cdump} on each address responding to @command{i2cdetect}. This may find the culprit.  Do not @command{i2cdump address 0x69}, the clock chip.
1202@item The chip driver is incorrectly finding a second chip on the bus and is accessing it. For example, with the Tyan 2688 with a w83781d at 0x29, use @command{modprobe ignore_range=0,0x00,0x28,0,0x2a,0x7f} to prevent access to other addresses. (@command{init=0} also req'd for the Tyan 2688).
1203@end enumerate
1204
1205
1206@node Section 4.30, Section 4.31, Section 4.29, Problems
1207@section Inserting modules slows down my board
1208
1209Generally this is caused by an overtemperature alarm output from
1210the sensor chip. This triggers hardware on the board which
1211automatically slows down the CPU clock. Be sure that your
1212temperature limits are above the temperature reading. Put
1213the new limits in @file{/etc/sensors.conf} and run @command{sensors -s}.
1214
1215
1216@node Section 4.31, Section 4.32, Section 4.30, Problems
1217@section Problems on particular motherboards
1218
1219The following boards have unique problems and solutions.
1220
1221
1222@anchor{Asus P4B}
1223@subsection Asus P4B
1224
1225See @file{prog/hotplug/README.p4b} if your SMBus master is not found.
1226
1227
1228@anchor{Tyan 2460 2462}
1229@subsection Tyan 2460, 2462
1230
1231See support tickets 805, 765, 781, 812, 813, and 867 for information.
1232
1233
1234@anchor{Tyan 2466}
1235@subsection Tyan 2466
1236
1237See support tickets 941, 840, and 841 for information.
1238
1239
1240@anchor{Tyan 2688}
1241@subsection Tyan 2688
1242
1243For board hangs, see support ticket 721 for information.
1244Also @ref{Section 4.29, Inserting modules hangs my board}.
1245
1246
1247@node Section 4.32, Section 4.33, Section 4.31, Problems
1248@section Problems on particular systems
1249
1250For IBM systems, see @file{README.thinkpad}.
1251
1252
1253@node Section 4.33, , Section 4.32, Problems
1254@section Problems on 2.6 kernels
1255
1256Not all drivers have been ported to 2.6. If your favorite driver is not
1257in 2.6, the reason is that nobody has ported it, or the ported code did
1258not get a proper review yet.
1259If you would like to port the driver, see the file
1260Documentation/i2c/porting-clients in the 2.6 kernel tree for help,
1261then send us the ported driver when you are done.
1262
1263@subsection i2c-viapro and via686a
1264Until kernel 2.6.11, there was a PCI resource conflict between
1265i2c-viapro (the SMBus driver for VIA bridges) and via686a (the integrated
1266sensors driver for VIA bridges). This caused the second loaded driver to
1267silently fail working. So do not load both i2c-viapro and via686a together
1268unless you have a recent kernel.
1269
1270@subsection Where are my EEPROMs?
1271The 2.6.14-rc1 kernel introduced the hwmon class, which groups all
1272hardware monitoring drivers in a logical way. The goal was to help
1273libsensors grab the relevant sensors information in /sys. In particular:
1274@itemize
1275@item libsensors will no more need to know about the underlying bus types
1276(I2C/SMBus, ISA or other);
1277@item libsensors will no more list non-hardware monitoring chips.
1278@end itemize
1279This explains why EEPROMs are no more displayed by @command{sensors}:
1280they are no hardware monitoring chips. The medium term plan is to drop
1281eeprom support for all Linux 2.6 kernels, as it didn't fit well in
1282the library code in the first place.
1283
1284Note that you can still obtain information about your EEPROMs by using
1285the dedicated perl scripts in @file{prog/eeprom}: @command{ddcmon},
1286@command{decode-dimms.pl}, @command{decode-edid.pl} and
1287@command{decode-vaio.pl}.
1288
1289
1290@node Help, Contribute, Problems, Top
1291@chapter How to Ask for Help
1292
1293@menu
1294* Section 5.1::  What to send us when asking for help
1295* Section 5.2::  What to do if a module won't insert?
1296* Section 5.3::  What to do if it inserts, but nothing happens?
1297* Section 5.4::  What to do if I read only bogus information?
1298* Section 5.5::  What to do if you have other problems?
1299* Section 5.6::  What if it just works like a charm?
1300* Section 5.7::  How do I update a ticket?
1301* Section 5.8::  How do I follow up on a ticket?
1302* Section 5.9::  Why did you decide not to support undocumented chips?
1303@end menu
1304
1305
1306@node Section 5.1, Section 5.2, , Help
1307@section What to send us when asking for help
1308
1309We are always willing to answer questions if things don't work out.
1310Post your question to our @uref{http://lists.lm-sensors.org/mailman/listinfo/lm-sensors, discussion list},
1311and not the individual authors,
1312unless you have something private to say.
1313
1314Instead of using email, you can also use the web-based support
1315area, at @uref{http://www.lm-sensors.org/wiki/FeedbackAndSupport}. You will be helped
1316just as fast, and others may profit from the answer too. You will be
1317emailed automatically when your question has been answered.
1318
1319Here's what you should send us:
1320
1321@itemize
1322@item The dmesg or syslog output if applicable
1323@item The output of (as root) @command{prog/detect/sensors-detect}
1324@item The output of @command{lsmod}
1325@item If a PCI chip problem:
1326@itemize
1327@item The output of @command{lspci -n}
1328@end itemize
1329@item If an I2C sensor chip problem:
1330@itemize
1331@item The output of (as root) @command{prog/detect/i2cdetect X}
1332where X = the bus number (run @command{i2cdetect} with no arguments to list the busses)
1333(please send this only if it's not all @samp{XX})
1334@item The output of (as root) @command{prog/dump/i2cdump X 0xXX}
1335where XX = the address of each chip you see in the output of @command{i2cdetect}. (run once for each chip)
1336(please send this only if it's not all @samp{ff})
1337@end itemize
1338@item If an ISA sensor chip problem:
1339@itemize
1340@item The output of (as root) @command{prog/dump/isadump 0x295 0x296} (only if it's not all @samp{XX})
1341@end itemize
1342@item Part numbers of chips on your motherboard you think are the sensor chips (look at your motherboard)
1343@item Motherboard type
1344@item Sensors version
1345@item Kernel version
1346@end itemize
1347
1348
1349@node Section 5.2, Section 5.3, Section 5.1, Help
1350@section What to do if a module won't insert?
1351
1352Did you use @command{modprobe} instead of @command{insmod}??? Don't use insmod.
1353
1354Were there unresolved symbols? Did you run @command{depmod -a}? Run
1355@command{depmod -a -e} to see where the symbol problem is.
1356
1357ALWAYS inspect the output of @command{dmesg}. That's where the error
1358messages come out!!! Don't rely on the generic message from @command{modprobe}.
1359If you still can't figure it out, send us the information
1360listed above.
1361
1362
1363@node Section 5.3, Section 5.4, Section 5.2, Help
1364@section What to do if it inserts, but nothing happens?
1365
1366For an ISA sensor chip, did you also @command{modprobe i2c-isa}? It must be inserted.
1367
1368For an I2C sensor chip, did you also @command{modprobe i2c-xxx} where xxx is your
1369I2C bus adapter? It must be inserted.
1370
1371Always inspect the output of @command{dmesg}. That's where the error
1372messages come out. If you still can't figure it out, send us the information
1373listed above.
1374
1375
1376@node Section 5.4, Section 5.5, Section 5.3, Help
1377@section What to do if I read only bogus information?
1378
1379It may be that this was a mis-detection: the chip may not be
1380present. If you are convinced there is something wrong, verify that you
1381indeed have the devices on your motherboard that you think you do.
1382Look at the motherboard and make sure. If you are still stuck,
1383please send us the usual information (@pxref{Help})
1384
1385
1386@node Section 5.5, Section 5.6, Section 5.4, Help
1387@section What to do if you have other problems?
1388
1389Again, send the output listed above.
1390
1391
1392@node Section 5.6, Section 5.7, Section 5.5, Help
1393@section What if it just works like a charm?
1394
1395Drop us a mail if you feel like it, mentioning the mainboard and
1396detected chip type. That way, we have some positive feedback, too!
1397
1398
1399@node Section 5.7, Section 5.8, Section 5.6, Help
1400@section How do I update a ticket?
1401
1402You can't. Only developers can. Follow up by emailing us
1403and reference your ticket number
1404in the subject. Please don't enter a new ticket with
1405follow-up information, email us instead. Thanks.
1406
1407
1408@node Section 5.8, Section 5.9, Section 5.7, Help
1409@section How do I follow up on a ticket?
1410
1411Follow up by emailing us
1412and reference your ticket number in the subject.
1413
1414
1415@node Section 5.9, , Section 5.8, Help
1416@section Why did you decide not to support undocumented chips?
1417
1418There are several reasons why we are generally not interested in writing
1419drivers for undocumented chips:
1420
1421@itemize
1422@item Writing a driver without a datasheet is much harder, as you have to
1423guess most things. Remember that, most of the time, we write drivers for fun
1424and for free, so there is no reason we would write a driver in conditions
1425that promise more pain than fun.
1426@item If we hit a problem, we are certain never to get any support from the
1427chip manufacturer. This means that we may spend days on code which will
1428finally never work.
1429@item There are several chips out there which are fully documented and lack
1430a driver. This is natural for us to give these the priority when we
1431finally have some spare time to spend on driver coding.
1432@item Hardware monitoring chips are not toys. Misprogramming them can
1433result in data loss or hardware breakage. This is obviously more likely
1434to happen with undocumented chips. This is a responsability we do not
1435want to endorse (the GPL is pretty clear than we are not legally
1436liable, but still).
1437@end itemize
1438
1439There are also several reasons why we do not want to support such drivers,
1440even if they were written by other people:
1441
1442@itemize
1443@item Problems are much more likely to happen with such drivers.
1444This means increased needs of support. User support if very
1445time-consuming and we are usually short of time.
1446@item Support should be done by the driver author (as only him/her knows
1447the driver and chip) but in the reality of facts, people will always ask
1448us for help if the driver is part of our package. Redirecting all user
1449requests to the driver's author manually is boring.
1450@item The lack of datasheet usually results in an original driver which
1451works relatively fine for its author, but will happen not to work
1452completely for other users. This means that the driver will need many
1453more additions and fixes than other drivers do, resulting in an increased
1454maitainance workload, which we can hardly afford. Of course this too should
1455be handled by the original driver author, but we never know whether he/she
1456will actually do the work.
1457@end itemize
1458
1459Lastly, there are other considerations, some of which are deliberately
1460political:
1461
1462@itemize
1463@item We do not want to trick hardware buyers into thinking that a chip is
1464fully supported under Linux when in fact it is only partly supported by a
1465driver which was written without a datasheet. Clearly stating that such
1466chips are not supported makes it much easier for anyone who really needs
1467fully working hardware monitoring under Linux to avoid motherboards with
1468these partly supported chips.
1469@item Drivers written without a datasheet are a pain for developers and
1470users, but are a complete win for the manufacturers of these chips:
1471they don't have to write the driver, they don't have to help us,
1472they don't have to support the users, and they still sell their
1473hardware. We do not want to encourage such a selfish behavior.
1474@end itemize
1475
1476That being said, authors of such drivers can still submit their code to
1477the Linux kernel folks for inclusion into Linux 2.6. Their driver may be
1478accepted there, under conditions.
1479
1480If such a driver is ever accepted into the Linux 2.6 tree, and someone
1481provides a patch to libsensors and/or sensors to add support for this
1482driver, we will apply it. This generic code is unlikely to cause trouble.
1483
1484
1485@node Contribute, Document Revisions, Help, Top
1486@chapter How to Contribute
1487
1488@menu
1489* Section 6.1::  How to write a driver
1490* Section 6.2::  How to get SVN access
1491* Section 6.3::  How to donate hardware to the project
1492* Section 6.4::  How to join the project mailing list
1493* Section 6.5::  How to access mailing list archives
1494* Section 6.6::  How to submit a patch
1495* Section 6.7::  How to REALLY help
1496* Section 6.8::  How to get release announcements
1497@end menu
1498
1499
1500@node Section 6.1, Section 6.2, , Contribute
1501@section How to write a driver
1502
1503See @file{doc/developers/new_drivers} in our package for instructions.
1504
1505
1506@node Section 6.2, Section 6.3, Section 6.1, Contribute
1507@section How to get SVN access
1508
1509For anonymous SVN read access, see the instructions on our
1510@uref{http://www.lm-sensors.org/wiki/Download, download page}.
1511
1512For write access, please contact us.
1513
1514
1515@node Section 6.3, Section 6.4, Section 6.2, Contribute
1516@section How to donate hardware to the project
1517
1518@uref{http://www.lm-sensors.org/wiki/FeedbackAndSupport, Contact us}.
1519
1520
1521@node Section 6.4, Section 6.5, Section 6.3, Contribute
1522@section How to join the project mailing lists
1523
1524There are two lists you can subscribe to:
1525
1526@itemize
1527@item A @uref{http://lists.lm-sensors.org/mailman/listinfo/lm-sensors, general discussion list},
1528meant for both development and user support. You do not need to be subscribed to post.
1529@item A @uref{http://lists.lm-sensors.org/mailman/listinfo/lm-sensors-commit, CVS commits list},
1530for watching the changes made to the CVS repositories. This list is read-only.
1531@end itemize
1532
1533
1534@node Section 6.5, Section 6.6, Section 6.4, Contribute
1535@section How to access mailing list archives
1536
1537The primary mailing list archive is at:
1538@uref{http://lists.lm-sensors.org/pipermail/lm-sensors/}.
1539It contains messages since October 28, 2001.
1540
1541There is another mailing list archive at:
1542@uref{http://news.gmane.org/gmane.linux.drivers.sensors}.
1543It contains messages since December 31, 2004.
1544This archive may also be accessed via a news reader:
1545@uref{nntp://news.gmane.org/gmane.linux.drivers.sensors}
1546and RSS:
1547@uref{http://rss.gmane.org/gmane.linux.drivers.sensors}.
1548
1549And last there is a legacy archive at:
1550@uref{http://archives.andrew.net.au/lm-sensors}.
1551It contains messages from October 28, 2001 through May 16, 2005.
1552
1553
1554@node Section 6.6, Section 6.7, Section 6.5, Contribute
1555@section How to submit a patch
1556
1557Check out the latest from CVS, then copy the directory to another
1558directory, and make your changes. Generate the diff with
1559@command{diff -u2 -r DIR1 DIR2}. Or you can generate the diff in CVS with
1560@command{cvs diff -u2}. Send us the patch in an email and tell us what it does.
1561
1562@node Section 6.7, Section 6.8, Section 6.6, Contribute
1563@section How to REALLY help
1564
1565Believe it or not, what we really need help with are:
1566@itemize
1567@item Answering email
1568@item Answering support tickets
1569@item Porting drivers to Linux 2.6
1570@item Creating a sensors.conf database
1571@item Reviewing patches
1572@end itemize
1573
1574If you are willing to help, simply join our
1575@uref{http://lists.lm-sensors.org/mailman/listinfo/lm-sensors, discussion list},
1576and we'll help you help us.
1577
1578
1579@node Section 6.8, , Section 6.7, Contribute
1580@section How to get release announcements
1581
1582We don't have a separate release announcement mailing list;
1583however, we put all our releases on freshmeat: @uref{http://freshmeat.net}
1584and you can register on our freshmeat project page  @uref{http://freshmeat.net/projects/lm_sensors}
1585to 'subscribe to new releases' and then freshmeat
1586will email you announcement.
1587
1588
1589@node Document Revisions, , Contribute, Top
1590@appendix Revision History of This Document
1591
1592@itemize
1593@item Rev 2.18 (JD) Removed version 1 specifics part, 2005-12-17
1594@item Rev 2.17 (JD) Added 5.9 (why we don't support undocumented chips),
1595        removed 6.9 (doesn't apply to the new mailing list), 2005-10-05
1596@item Rev 2.16 (JD) Added 4.33.2, 2005-09-06
1597@item Rev 2.15 (JD) Updates, including mailing-list change, 2005-05-21
1598@item Rev 2.14 (MDS) Updated 4.12, 2004-11-26
1599@item Rev 2.13 (JD) Added 4.6.1, updated 4.7, 2004-06-23
1600@item Rev 2.12 (JD) Updated 4.27, 2004-04-11
1601@item Rev 2.11 (JD) Various updates, 2004-01-18
1602@item Rev 2.10 (MDS) Various updates, 2004-01-03
1603@item Rev 2.9 (CP) Converted to Gnu texinfo format, 2002-09-10
1604@item Rev 2.8 (MDS) Minor updates 2002-07-10, released with lm_sensors 2.6.4
1605@item Rev 2.7 (MDS) Minor updates 2002-04-25
1606@item Rev 2.6 (MDS) Minor updates 2002-01-15, released with lm_sensors 2.6.3
1607@item Rev 2.5 (MDS) Minor updates 2001-11-11, released with lm_sensors 2.6.2
1608@item Rev 2.4 (MDS) Minor updates 2001-07-22
1609@item Rev 2.3 (MDS) General update, 2001-02-24, released with lm_sensors 2.6.0.
1610@item Rev 2.2 (Frodo) Corrections for lm_sensors 2.4, 1999-09-20
1611@item Rev 2.1 (Frodo) Corrections for lm_sensors 2.2, 1999-01-12
1612@item Rev 2.0 (Frodo) Major revision for lm_sensors 2.1, 1998-12-29
1613@item Rev 1.10 (Frodo) Modified 3.8, updated some other things, 1998-09-24
1614@item Rev 1.9 (Frodo) Added 3.15, 1998-09-06
1615@item Rev 1.8 (Frodo) Added 3.14, 1998-09-05
1616@item Rev 1.7 (Phil) Added 3.13 and some other minor changes, 1998-09-01
1617@item Rev 1.6 (Frodo) Added 4, 4.1, 4.2, 4.3, 4.4, 4.5, 1998-09-01
1618@item Rev 1.5 (Frodo) Added 2.3, 2.4, 3.9, 3.10, 3.11, 1998-08-26
1619@item Rev 1.4 (Frodo) Added some more Winbond information, and 3.5-3.8, 1998-08-17
1620@item Rev 1.3 (Phil) Added info on the Winbond chip, 1998-08-16
1621@item Rev 1.2 (Frodo) Adapation, 1998-08-10
1622@item Rev 1.1 (Phil) Modifications, 1998-08-09
1623@item Rev 1.0 (Phil) First version, 1998-08-03
1624@end itemize
1625
1626@bye
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