On Fri, 2011-03-04 at 13:53 -0500, Andrew Lutomirski wrote: > On Fri, Mar 4, 2011 at 1:50 PM, Andrew Lutomirski <luto@xxxxxxx> wrote: > > On Fri, Mar 4, 2011 at 12:57 PM, Guenter Roeck > > <guenter.roeck@xxxxxxxxxxxx> wrote: > >> The following patch series adds support for NCT6775F and NCT6776F to the > >> w83627ehf driver. It also includes some cleanup and adds support for > >> the fourth temperature sensor on W83677HG-B. > >> > >> No code changes since v4. Resubmitting and widening audience in the hope that > >> someone may find the time to review the changes prior to the next commit window. > > > > I'm not sure my review is worth much, but the driver seems to work. I've tested > > fan speed measurement, changing pwm2_enable to 1, changing the fan speed, > > and changing back to 5. Everything looks good. > > > > The only weird thing I noticed is that, the first time I ran sensors, I got: > > fan2: 0 RPM (min = 0 RPM, div = 64) > > and thereafter I get > > fan2: 136 RPM (min = 0 RPM, div = 64) ALARM > > > > I suspect (although I haven't checked) that sensors is just reading > > div after it's already changed to 64. > > I'll add one more weird thing on my NCT6775F. > > [root@midnight w83627ehf.656]# echo 3200 >fan2_min > [root@midnight w83627ehf.656]# cat fan2_div > 8 > [root@midnight w83627ehf.656]# cat fan2_input > 133 > [root@midnight w83627ehf.656]# cat fan2_div > 16 > [root@midnight w83627ehf.656]# cat fan2_input > 133 > [root@midnight w83627ehf.656]# cat fan2_div > 32 > [root@midnight w83627ehf.656]# cat fan2_input > 133 > [root@midnight w83627ehf.656]# cat fan2_div > 64 > [root@midnight w83627ehf.656]# cat fan2_input > 132 > [root@midnight w83627ehf.656]# cat fan2_div > 64 This is actually as expected. rpm calculation is rpm = 1350000 / (rpm_reg * div) In your case, this translates to rpm_reg * div ~ 8500 so for div < 64, the value of rpm_reg is larger than 255. If this happens, the driver automatically increases fan_div until rpm_reg is smaller than 255. Reason for this is that while the chip has a 16 bit rpm register, the min speed register is still only 8 bit wide. Plus, at least some versions of NCT6775F report an rpm of 0 if the divisor is set too low. Thanks, Guenter _______________________________________________ lm-sensors mailing list lm-sensors@xxxxxxxxxxxxxx http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
