On Fri, Jan 27, 2012 at 06:52:17PM -0500, CC wrote: > On Fri, Jan 27, 2012 at 11:41 PM, Guenter Roeck > <guenter.roeck@xxxxxxxxxxxx> wrote: > > Hi, > > > > On Fri, Jan 27, 2012 at 12:49:48PM -0500, CC wrote: > > [ ... ] > >> > > >> > I tested all three fan outputs. Another thing is weird: pwm1_mode has > >> > its meaning reversed (it's a 3-pin connector and the value 1 is DC > >> > mode, in contrast to pwm2 and the documentation). > >> > > > You lost me there. pwm1 supports both DC and PWM. pwm1_mode should return 0 for DC mode, > > 1 for pwm mode. The other pwm channels only support pwm mode on the NCT6776F, thus > > pwm2_mode and pwm3_mode should both return 1. > > > > Are you saying that reading pwm1_mode returns 1, and pwm2_mode and pwm3_mode > > both return 0 ? > > > > Thanks, > > Guenter > > Maybe my reasoning is wrong... > > We have that > > * fan1 is linked to pwm1 > * fan2 is linked to pwm2 > * fan4 can only be monitored > * fan5 is linked to pwm3 > > Only fan2 has a 4-pin connector and could thus be controlled by PWM, > the others can only be controlled by voltage. Let's assume all fans to > be in manual mode. > > * regardless of pwm1, fan1 runs at full speed when pwm1_mode returns 0 > * the fan's speed can be controlled by pwm1 when pwm1_mode returns 1 > > So DC mode is only (correctly) activated when pwm1_mode returns 1. > > * fan2 stops when pwm2 returns 0 and pwm2_mode also returns 0 > * fan2 runs slowly when pwm2 returns 0 and pwm2_mode returns 1 > > I interpret this as DC mode being used when pwm2_mode returns 0. > > * regardless of pwm3, fan5 runs at full speed whenever pwm3_mode returns 0 > * the fan's speed can be controlled when pwm1_mode returns 1 > > So DC mode is only (correctly) activated when pwm3_mode returns 1. > On pwm2 and pwm3, the chip doesn't even support DC mode (per datasheet). So setting those to 0 is, at best, undefined, and should not yield any results. I guess the "bug" here is that pwm2_mode and pwm3_mode are writable for the NCT6776F. We should really reject setting DC mode for those attributes. Regarding pwm1_mode, maybe the board plays with the pwm output and converts it to a voltage - really hard to say. Question really is - what are the powerup settings ? Presumably those should be correct. Thanks, Guenter _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
