2014/1/9 Jean Delvare <khali@xxxxxxxxxxxx> > > Hi Martin, Hi Jean, thanks for your extensive reply! > > My questions: > > 1. coretemp outputs 5 temperatures. The last 4 are the cores, but what > > is the value of the first one? (my guess: the temperature of the > > highest core) > > The first temperature reported by coretemp is the "CPU package > temperature". I can't remember if it's a separate sensor or just > computed by the hardware as the maximum of the core temperatures. Check! > > 2. coretemp temperatures have (according to sensors -u) a _max, _crit > > and _crit_alarm. How are these values determined? Does lm_sensors have > > a database of existing cpu's and their max temperature specifications? > > On recent Intel processors these values are read from the CPU itself. > On older processors the driver has heuristics to figure them out. It > may get them wrong in a few cases. Check the driver documentation for a > list of known limits for older processors. > > http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/hwmon/coretemp > > With a Core i5 you should be on the safe side. Check! > > 3. (follow-up on Q2) what is the difference between _max and _crit? > > What happens when each of them is reached? What is the role of > > _crit_alarm and how will the alarm be noticed? > > For the coretemp driver, _max is the temperature at which point all > cooling options should be enabled at full throttle. _crit is the > temperature at which the CPU integrity is no longer guaranteed. You > don't want to reach that temperature, ever. > > _crit_alarm is raised when the measured (_input) temperature goes above > the _crit limit. This is checked by polling as the coretemp driver > currently doesn't have a notification mechanism. libsensors doesn't > support such notifications anyway. This should be added but I don't > have the time for that. Check! > > 4. (follow-up on Q3) how can I change the values for _max and _crit? I > > tried 'set temp1_max 60' but that doesn't work. (sensors -s complains) > > These are read-only limits specific to your CPU model. You don't get to > change them, sorry. Clear :-) > > 5. what is the difference between fan1_alarm and fan1_beep? > > fan1_alarm triggers when fan1_input goes below fan1_min. It is > read-only. fan1_beep is writable and tells whether the alarm triggering > will result in your system beeping or not. Note that your board must be > properly wired (i.e. beep output of the monitoring chip routed to the > on-board buzzer or PC speaker) for this to work, which is unfortunately > not always the case. Check! (I tested my board, it doesn't beep..) > > 6. (follow-up on Q5) how do I set fan1_alarm? set fan1_alarm 1 doesn't > > work. (sensors -s complains) > > You don't, this is a read-only value which gets set by the hardware by > comparing fan1_input with fan1_min. It is set and cleared by the > hardware. What were you trying to achieve by setting it to 1 manually? I was expecting that I could enable/disable a notification (e.g. a beep from the PC speaker), but your explanation makes more sense (from the it8728 engineer perspective). Clear! > > 7. it8728 reports 3 different temps. When CPU is at full load, one of > > them increases, but the value is much lower than the one reported by > > coretemp (about 10 degrees lower). sensors outputs that it is Intel > > PECI. According to the explanation on Wikipedia > > (http://en.wikipedia.org/wiki/Platform_Environment_Control_Interface) > > the temperature should be negative and increase towards 0 when cpu > > temperature rises. Why does sensors show different values? > > PECI is the low level specification. Users wouldn't understand that > sensors returns negative, relative temperature values. So all drivers > supporting PECI compute the actual temperature based on the negative > PECI value and the base temperature (maximum temperature supported by > the component being monitored, the CPU in this case.) For some drivers > (such as it87) this is even done by the hardware itself. This assumes > that the base temperature is known and correct, which is unfortunately > not always the case. In the case of the IT8728F chip, the base > temperature should be set by the BIOS depending on your CPU model. The > fact that the values differ between coretemp and it87 suggests that the > BIOS and the coretemp driver disagree about the base temperature (which > matches temp1_crit for the coretemp driver.) Clear again. coretemp _crit temperature is correct, so I have to adjust the IT8728F cpu temperature with 10 degrees: compute temp3 @+10,@+10 (Note: I wonder if this is influenced by my BIOS settings, which allows me to change the temperature for CPU warning.) > > 8. it8728 shows another two temps. Likely one case temp and the other > > one the south bridge? How can I find out? > > Check what the BIOS says, it typically shows two temperatures so that > should tell you what temp2 is. Check if the motherboard documentation > mentions anything. Then experiment by yourself (see what makes each > temperature rise the most.) It is possible that the 3rd temperature is > just noise. Ok, a simple cpu load test showed that temp3 is the cpu temp. When I compare with the bios, I believe that temp1 is the system/case temp. In that case temp2 is the noise, but the difference between temp1 and temp2 is only about 3-4 degrees. The user manual of my motherboard doesn't have much information about the temperature sensors. > > 9. (from FAQ) "Do you have a database of sensors.conf entries for > > specific boards? > > No. Good idea though. If you would like to set one up on your website > > send us mail and we will set up a link to it." > > Why hasn't this been setup yet? Some sort of a database is at the > > wiki, but doesn't contain many boards. Is any help still appreciated? > > Is it just a table of manufacturer, type, sensors.conf file? (and > > maybe some user registrations and comments by registered users?) > > It has not been setup because nobody took the time and energy to do so. > Yes, it's "only" a set of configuration files indexed by board > manufacturer/model. But you need to store them somewhere in a safe way, > provide a way to search and retrieve them, provide a way to add and > amend them (with protection from spam or any form of abuse.) You are > welcome to help, but no, this isn't a trivial task. I started a new thread on this one. > > P.S. if answers can be found somewhere.. please let me know where to > > find the documentation! > > Some parts of http://www.lm-sensors.org/wiki/Documentation are worth a > read, but it did not contain an answer to all your questions above. Pfhew! :-) I currently believe that my last two questions are: 10. How are temp1_min and temp1_max determined for the it8728 reportes temperatures? 11. What is temp1_type and temp1_offset? Thanks in advance again! Martin _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
