Hi Charles, Please keep the list CC'd. On Sun, 04 Dec 2011 12:29:34 +0530, Charles wrote: > On 04/12/11 01:44, Jean Delvare wrote: > > I finally gave it a try myself. Please fetch: > > http://khali.linux-fr.org/devel/misc/fancontrol > > and give it a try, it should work OK with multiple fans controlled by > > one PWM output. > > Thanks Jean ::) > > Tested; no error messages and GKrellM shows sane processor core > temperatures and fan speeds. > > Sorry for the incomplete initial report: > * I had applied the suggested workaround (thanks Jean and Guenter). Hmm. Please test the updated version of the script _without_ the workaround applied. That's the whole point of the update. > * Connecting the case exahust fan to CPU_FAN is not an option because > pwmconfig does not control it then, although it can control the stock > Intel fan on the same header (subject to the ~1100 RPM minimum). Most likely because the CPU fan header is a 4-pin header, and the Intel CPU fan has 4 wires, while the case fan headers are 3-pin with a 3-wire fan. On 4-pin headers, the PWM signal is separated from the power. So you can't control a 3-wire fan plugged in a 4-pin header (the PWM signal is on the unconnected pin [1].) This also explains the minimum speed of 4-wire PWM-controlled fans. This is per design. If the minimum speed doesn't please you, you have to either buy a different fan with a lower minimum, or lower the fan voltage using a serial resistor (Noctua amongst several other fan vendors includes such resistors in many of their product packages.) [1] Some boards have jumpers that will let you turn a 4-pin fan header into a 3-pin one. You loose the benefits of 4-wire fans (such as linear fan speed control and reliable readings at low speed) but are no longer affected by the arbitrary fan minimum then. > * PWR_FAN is not speed-controlled. > > The present situation is not satisfactory (not an lm_sensors issue, > reporting in case someone in a similar situation finds this) because the > processor and case fans have very different signal/speed characteristics > so, for example, the processor fan runs at 1400 while the case runs at > 700 and the case exhaust air is warmer than ideal. Indeed, it is only recommended to connect similar fans to the same control output. There's a reason why board makers often connect the case fans together, but usually have a separate fan control for the CPU(s). -- Jean Delvare _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
